Heating/cooling system

ABSTRACT

An object is to provide a heating/cooling system capable of achieving reduction of power consumption, and enhancement of performance in a heating/cooling system usable in such a manner as to be switched to be hot/cold. The heating/cooling system having a storage chamber usable in such a manner as to be switched to be hot/cold, comprises: a refrigerant circuit comprising a compressor, a gas cooler, a pressure reducing device, an evaporator and the like, containing carbon dioxide sealed as a refrigerant therein, and having a supercritical pressure on a high-pressure side; a radiator through which the refrigerant flowing out of the gas cooler flows before entering the pressure reducing device; and an air blower which sends air through the gas cooler, the inside of the storage chamber is heated by the radiator, the inside of the storage chamber is cooled by the evaporator, and the air blower is stopped in a case where the inside of the storage chamber is heated by the radiator.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a heating/cooling system having astorage chamber usable in a switched hot/cold state.

2. Description of the Related Art

As shown in FIG. 17, this type of heating/cooling system has heretoforecomprised a storage chamber 101 partitioned into a cooling chamber 102and a heating chamber 103 by an insulated wall, and a machine chamber109 disposed under the storage chamber 101. Moreover, the machinechamber 109 contains a compressor 111, a gas cooler 112, a capillarytube 116 which is pressure reduction means and the like, and constitutesa refrigerant circuit 110 together with an evaporator 117. An electricheater 180 is disposed in the heating chamber 103, and air heated by theelectric heater 180 is sent into the heating chamber 103 by a fan 128 tothereby heat the heating chamber 103.

Here, an operation of a conventional heating/cooling system 400 will bedescribed with reference to FIG. 17. When an operation of the fan 128 isstarted by a control device (not shown), and electric power is suppliedto the electric heater 180, the air heated by the electric heater 180 iscirculated in the heating chamber 103 by the fan 128. Accordingly, theinside of the heating chamber 103 is heated.

Moreover, the control device starts the operation of a fan 127, andstarts a driving element (not shown) of the compressor 111. Accordingly,a low-pressure refrigerant gas is sucked and compressed in a cylinder ofa compression element (not shown) of the compressor 111 to constitute ahigh-temperature/pressure refrigerant gas, and the gas is discharged tothe gas cooler 112.

Furthermore, the refrigerant gas releases heat by the gas cooler 112,and enters the capillary tube 116 via an internal heat exchanger 145,the pressure is lowered in the tube, and the gas flows into theevaporator 117. There the refrigerant evaporates, and absorbs the heatfrom ambient air to thereby perform a cooling function. It is to benoted that the air cooled by evaporation of the refrigerant in theevaporator 117 is circulated in the cooling chamber 102 by the operationof the fan 127 to cool the inside of the cooling chamber 102. Thus, inthe conventional heating/cooling system, the inside of the heatingchamber 103 has heretofore been heated by the electric heater 180, andthe cooling chamber 102 is cooled by the evaporator 117 of therefrigerant circuit 110 (see, e.g., Japanese Patent Application LaidOpen No. 6-18156).

Here, in recent years, a hot/cold switch-usable heating/cooling systemhas also been developed in which both a heating member such as anelectric heater, and an evaporator are disposed in one storage chamber.When the storage chamber is heated, a heater is operated to heat thestorage chamber. When the storage chamber is cooled, the operation ofthe electric heater is stopped, the operation of the compressor isstarted, and the refrigerant is evaporated by the evaporator to cool thestorage chamber. However, as described above, the storage chamber isheated by a heating member such as an electric heater, and therefore aproblem has occurred that power consumption remarkably increases.

SUMMARY OF THE INVENTION

An object of the present invention is to reduce power consumption andenhance performance in a hot/cold switch-usable heating/cooling systemin order to solve the above-described technical problems.

According to the present invention, there is provided a heating/coolingsystem having a storage chamber usable in such a manner as to beswitched to be hot/cold, comprising: a refrigerant circuit comprising acompressor, a gas cooler, a pressure reducing device, an evaporator andthe like, containing carbon dioxide sealed as a refrigerant therein, andhaving a supercritical pressure on a high-pressure side; a radiatorthrough which the refrigerant flowing out of the gas cooler flows beforeentering the pressure reducing device; and an air blower which sends airthrough the gas cooler, the inside of the storage chamber being heatedby the radiator, the inside of the storage chamber being cooled by theevaporator, and the air blower being stopped in a case where the insideof the storage chamber is heated by the radiator.

According to the heating/cooling system of the present invention, carbondioxide having satisfactory heating characteristic is used as therefrigerant. Accordingly, to cool the inside of the storage chamber, theinside is cooled by the evaporator. To heat the inside of the storagechamber, the inside of the storage chamber can be heated by therefrigerant passed through the gas cooler on the high-pressure side.Accordingly, since the inside of the storage chamber can be heatedwithout using any heating member such as an electric heater, powerconsumption can be reduced as compared with the heating by the electricheater.

Especially, when the inside of the storage chamber is heated by theradiator, the air blower is stopped. Therefore, heat is conveyed to theradiator without radiating the heat from the refrigerant in the gascooler, and a heating capability inside the storage chamber can beenhanced.

Moreover, in the heating/cooling system of the present invention, thecompressor in the above-described invention comprises first and secondcompression elements, and the second compression element compresses therefrigerant compressed by the first compression element. The compressorcomprises an intermediate cooling circuit comprising a heat exchangerfor cooling the refrigerant compressed by the first compression element,and allowing the second compression element to suck the refrigerant, andthe heat exchanger is integrally disposed in the gas cooler.

According to the present invention, in addition to the above-describedinvention, when a two-stage compression system compressor comprisingso-called intermediate cooling circuit is used, to heat the inside ofthe storage chamber, heat radiation in the heat exchanger of theintermediate cooling circuit is invalidated, and the heat can beconveyed to the radiator.

Moreover, in the above-described inventions, the heating/cooling systemof the present invention further comprises an internal heat exchangerfor exchanging the heat between the refrigerant which has flown out ofthe gas cooler and the refrigerant which has flown out of theevaporator, and the refrigerant is passed through the radiator beforereaching the internal heat exchanger.

According to the present invention, in addition to the above-describedinventions, the system comprises the internal heat exchanger forexchanging the heat between the refrigerant which has flown out of thegas cooler and the refrigerant which has flown out of the evaporator. Inthis case, the refrigerant is passed through the radiator beforereaching the internal heat exchanger. Therefore, the inside of thestorage chamber can be heated by the refrigerant before the temperatureof the refrigerant drops in the internal heat exchanger.

Moreover, in the above-described inventions, the heating/cooling systemof the present invention comprises channel control means for controllingrefrigerant circulation into the radiator and the evaporator, and anevaporator is separately disposed for passing the refrigerant throughthe radiator, and evaporating the refrigerant in a case where therefrigerant circulation into the evaporator is interrupted.

According to the present invention, in addition to the above-describedinventions, in a case where the inside of the storage chamber is heated,the refrigerant circulation into the evaporator is broken by the channelcontrol means, and the refrigerant can be evaporated by the separatelydisposed evaporator. Therefore, even when the radiator and evaporatorfor heating/cooling the inside of the storage chamber are disposed inthe storage chamber, the storage chamber can be heated/cooled withoutany trouble.

Moreover, according to the present invention, there is provided aheating/cooling system having a storage chamber usable in such a manneras to be switched to be hot/cold, comprising: a refrigerant circuitcomprising a compressor, a radiator, a pressure reducing device, anevaporator and the like, containing carbon dioxide sealed as arefrigerant therein, and having a supercritical pressure on ahigh-pressure side; and a partition member capable of dividing thestorage chamber in an insulated manner so that the inside of the storagechamber is heated by the radiator, and cooled by the evaporator. Thepartition member divides the storage chamber in such a manner that onechamber is heated by the radiator, and the other chamber is cooled bythe evaporator.

According to the heating/cooling system of the present invention, theinside of the storage chamber can be heated by the radiator, and cooledby the evaporator using carbon dioxide having a satisfactory heatingcharacteristic as the refrigerant. Accordingly, the inside of thestorage chamber can be heated without using any heating member such asan electric heater. Even when the heating member including the electricheater or the like is used, a capacity of the heating member can bereduced, and therefore the power consumption can be reduced.

Furthermore, when the storage chamber is divided by the partitionmember, a ratio of a heating region in which the inside of the storagechamber is heated by the radiator to a cooling region in which theinside of the storage chamber is cooled by the evaporator can bechanged.

Moreover, in the above-described inventions, the heating/cooling systemof the present invention further comprises: a gas cooler for radiatingheat from the refrigerant; a separate evaporator for evaporating therefrigerant; and channel control means for controlling refrigerantcirculation with respect to the radiator, the gas cooler, and both theevaporators.

According to the present invention, in addition to the above-describedinventions, when the channel control means is controlled, the heat isradiated from the refrigerant by the gas cooler, the refrigerant isevaporated by the evaporator for cooling the storage chamber, and thenthe whole storage chamber can be cooled.

Moreover, when the channel control means is controlled, the heat isradiated from the refrigerant by the radiator, the refrigerant isevaporated by the evaporator disposed separately from the evaporator forcooling the storage chamber, and then the whole storage chamber can beheated.

Accordingly, the inside of the storage chamber can be entirely heated orcooled, and convenience of the heating/cooling system can be enhanced.

Furthermore, in the heating/cooling system of the present invention, thecompressor in the above-described invention comprises first and secondcompression elements; and an intermediate cooling circuit for coolingthe refrigerant compressed by the first compression element of thecompressor, and thereafter allowing the second compression element tosuck the refrigerant. In a case where the inside of the storage chamberis heated by the radiator, the cooling of the refrigerant in theintermediate cooling circuit is substantially invalidated.

According to the present invention, in addition to the above-describedinventions, after cooling the refrigerant compressed by the firstcompression element, the refrigerant is sucked into the secondcompression element by the intermediate cooling circuit. Therefore, thetemperature of the refrigerant gas discharged from the secondcompression element of the compressor can be lowered. Accordingly, thecooling capability can be enhanced.

Furthermore, when the inside of the storage chamber is heated by theradiator, the cooling of the refrigerant in the intermediate coolingcircuit is substantially invalidated. Accordingly, the refrigerant gasdischarged from the second compression element of the compressor can bemaintained at high temperature, and the heating capability in theradiator can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a refrigerant circuit diagram of a heating/cooling system ofone embodiment of the present invention (Embodiment 1);

FIG. 2 is a refrigerant circuit diagram showing a flow of refrigerant ina mode in which a storage chamber 3 is used as a cooling chamber;

FIG. 3 is a refrigerant circuit diagram showing a flow of refrigerant ina mode in which the storage chamber 3 of FIG. 1 is used as a heatingchamber;

FIG. 4 is a refrigerant circuit diagram of the heating/cooling systemaccording to another embodiment of the present invention (Embodiment 2);

FIG. 5 is a refrigerant circuit diagram showing a flow of refrigerant ina mode in which chambers 3 and 4 of FIG. 4 are used as cooling chambers;

FIG. 6 is a refrigerant circuit diagram showing a flow of refrigerant ina mode in which the chamber 3 of FIG. 4 is used as the cooling chamber,and the chamber 4 is used as a heating chamber;

FIG. 7 is a refrigerant circuit diagram showing a flow of refrigerant ina mode in which the chambers 3 and 4 of FIG. 4 are used as heatingchambers;

FIG. 8 is a refrigerant circuit diagram of a heating/cooling systemaccording to another embodiment of the present invention (Embodiment 3);

FIG. 9 is a refrigerant circuit diagram showing a flow of refrigerant ina mode in which the chambers 3 and 4 of the heating/cooling system ofFIG. 8 are used as the cooling chambers;

FIG. 10 is a refrigerant circuit diagram showing a flow of refrigerantin a mode in which the chamber 3 of the heating/cooling system of FIG. 8is used as the cooling chamber, and the chamber 4 is used as the heatingchamber;

FIG. 11 is a refrigerant circuit diagram showing a flow of refrigerantin a mode in which the chambers 3 and 4 of the heating/cooling system ofFIG. 8 are used as the heating chambers;

FIG. 12 is a refrigerant circuit diagram of an open showcase accordingto still another embodiment of the present invention (Embodiment 4);

FIG. 13 is a longitudinal side view showing an operation in a mode inwhich storage chambers 270, 271, 272, and a chamber 273 of the openshowcase of FIG. 12 are used as the cooling chambers;

FIG. 14 is a longitudinal side view showing an operation in a mode inwhich the storage chambers 270, 271 are used as the heating chambers,and the storage chamber 272 and the chamber 273 are used as the coolingchamber in the open showcase of FIG. 12;

FIG. 15 is a longitudinal side view showing an operation in a mode inwhich the storage chambers 270, 271, 272 are used as the heatingchambers, and the storage chamber 273 is used as the cooling chamber inthe open showcase of FIG. 12;

FIG. 16 is a longitudinal side view showing a mode in which the storagechambers 270, 271, 272 and the chamber 273 are used as the heatingchambers in the open showcase of FIG. 12; and

FIG. 17 is an internal constitution diagram of a conventionalheating/cooling system.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention will be described hereinafter withreference to the drawings.

Embodiment 1

FIG. 1 is a schematic constitution diagram of a heating/cooling system100 according to one embodiment to which the present invention has beenapplied. It is to be noted that the heating/cooling system of thepresent invention is usable in a showcase, an automatic vending machine,an air conditioner, a cold/hot storage or the like.

In FIG. 1, reference numeral 1 denotes a storage chamber of theheating/cooling system 100, and the storage chamber 1 is surrounded withan insulating member. The inside of the storage chamber 1 is divided byan insulated wall 7, one chamber (on the left side of the insulated wall7 in FIG. 1) is used as a cooling chamber 2, and the other chamber (onthe right side of the insulated wall 7 in FIG. 1) is used as a storagechamber 3.

In the cooling chamber 2, an evaporator 17 for evaporating refrigerant,and a fan 27 for sending (circulating) air which has exchanged heat withthe evaporator 17 to the cooling chamber 2 are disposed. It is to benoted that the evaporator 17 is disposed separately from an evaporator18 described later. The refrigerant can be evaporated by the evaporator17 even in a case where refrigerant circulation into the evaporator 18is interrupted by the evaporator 17.

Moreover, in the storage chamber 3, a radiator 14, an electric heater80, the above-described evaporator 18, and a fan 28 for sending(circulating) the air which has exchanged heat with the radiator 14 orthe evaporator 18, or air heated by the electric heater 80 into achamber 4 are disposed. Moreover, the inside of the storage chamber 3 isheated by the radiator 14, and the inside of the storage chamber 3 iscooled by the evaporator 18. It is to be noted that the electric heater80 heats the inside of the storage chamber 3, and the electric heater 80can compensate the heating in the storage chamber 3 by the radiator 14.

On the other hand, in FIG. 1, reference numeral 10 denotes a refrigerantcircuit, and comprises a compressor 11, a gas cooler 12, the radiator14, an expansion valve 16 which is a pressure reducing device, theevaporators 17 and 18 and the like.

That is, a refrigerant discharge tube 34 of the compressor 11 isconnected to an inlet of the gas cooler 12. Here, the compressor 11 ofthe present embodiment is an internal intermediate pressure typetwo-step compression system rotary compressor, has a driving element(not shown), and first and second rotary compression elements (notshown) driven by this driving element in a sealed container 11A, and isconstituted in such a manner as to compress the refrigerant compressedby the first rotary compression element by the second rotary compressionelement.

In the figure, reference numeral 30 denotes a refrigerant introducingtube for introducing the refrigerant to the first rotary compressionelement of the compressor 11, and one end of the refrigerant introducingtube 30 communicates with a cylinder of the first rotary compressionelement. The other end of the refrigerant introducing tube 30 isconnected to an outlet of an internal heat exchanger 45 described later.

In the figure, reference numeral 32 denotes a refrigerant introducingtube for introducing the refrigerant compressed by the first rotarycompression element to the second rotary compression element. Therefrigerant introducing tube 32 is disposed in such a manner as to passthrough an intermediate cooling circuit 150 outside the compressor 11.Here, the intermediate cooling circuit 150 is a refrigerant circuitcomprising a heat exchanger 152 for cooling the refrigerant compressedby the first rotary compression element, and thereafter allowing thesecond rotary compression element to suck the refrigerant. That is, therefrigerant compressed by the first rotary compression element isallowed to flow into the intermediate cooling circuit 150 outside thecompressor 11 from the refrigerant introducing tube 32, cooled whilepassing,through the radiator 14, and sucked into the second rotarycompression element. The heat exchanger 152 is disposed integrally withthe gas cooler 12, and also serves as an air blower 22 for passing airthrough the gas cooler 12.

The refrigerant discharge tube 34 is a refrigerant pipe for dischargingthe refrigerant compressed by the second rotary compression element tothe gas cooler 12.

A refrigerant pipe 36 connected to the outlet of the gas cooler 12 isconnected to the internal heat exchanger 45. The internal heat exchanger45 exchanges heat between the refrigerant which has flown out of the gascooler 12 on a high-pressure side, and the refrigerant which has flownout of the evaporator 17 or 18 on a low-pressure side. A refrigerantpipe 37 connected to the outlet of the internal heat exchanger 45 isconnected to an inlet of the evaporator 17 of the cooling chamber 2 viathe expansion valve 16.

Here, a first bypass circuit 140 is branched midway in the refrigerantpipe 36. The first bypass circuit 140 is disposed,in such a manner as toextend through the radiator 14 disposed in the storage chamber 3, andthe refrigerant which has flown out of the gas cooler 12 before enteringthe expansion valve 16 and before reaching the internal heat exchanger45 can be passed through the radiator 14 by the first bypass circuit140.

Moreover, the first bypass circuit 140 extending from the radiator 14 isconnected to the refrigerant pipe 36 on the outlet side of anelectromagnetic valve 170 on an inlet side of the internal heatexchanger 45. The electromagnetic valve 170 and another electromagneticvalve 172 are disposed as channel control means for controllingrefrigerant circulation into the radiator 14 in a piping on a downstreamside of a branch of the first bypass circuit 140 of the refrigerant pipe36, and on the inlet side of the radiator 14 of the first bypass circuit140. The electromagnetic valves 170 and 172 are controlled in such amanner as to open/close by a control device (not shown). It is to benoted that the refrigerant circulation into the radiator 14 is notlimited to control of the respective electromagnetic valves 170 and 172,and the refrigerant circulation into the radiator 14 may be controlledusing and switching a three-way valve.

Moreover, a second bypass circuit 42 is branched from a middle portionof the refrigerant pipe 37 extending from the expansion valve 16. Thesecond bypass circuit 42 is disposed in such a manner as to pass throughthe evaporator 18 disposed in the storage chamber 3, and thereafterextend together with a refrigerant pipe 38 extending from the evaporator17. In a piping on the inlet side of the evaporator 18, anelectromagnetic valve 65 is disposed as the channel control means forcontrolling the refrigerant circulation into the evaporator 18.

Here, in the refrigerant circuit 10, carbon dioxide (CO₂) which isecological for global environment as the refrigerant and which isnatural refrigerant is sealed in consideration of combustibility,toxicity and the like, and the circuit has a supercritical pressure on ahigh-pressure side.

Moreover, the above-described electromagnetic valves 65, 170, 172 arecontrolled in such a manner as to open/close by control devices (notshown), respectively. It is to be noted that the control device iscontrol means for controlling the heating/cooling system 100, and inaddition to the respective electromagnetic valves 65, 170, 172,operations of the compressor 11, air blower 22, fans 27, 28 and the likeare also controlled.

(1) Mode to use Storage Chamber 3 as Cooling Chamber

Next, an operation of the heating/cooling system 100 constituted asdescribed above according to the present invention will be described.First, a mode to use the storage chamber 3 as the cooling chamber forcooling articles will be described with reference to FIG. 2. FIG. 2 is arefrigerant circuit diagram showing a flow of refrigerant in this mode.

The electromagnetic valve 170 is opened, the electromagnetic valve 172is closed, and the first bypass circuit 140 is blocked by the controldevice (not shown). Accordingly, since the refrigerant circulation intothe radiator 14 is interrupted, the refrigerant which has flown out ofthe gas cooler 12 does not flow into the radiator 14, and flows into theinternal heat exchanger 45 as such. Moreover, the control device opensthe electromagnetic valve 65 to open the second bypass circuit 42.Accordingly, the refrigerant from the expansion valve 16 flows into theevaporator 18. It is to be noted that in FIGS. 2 and 3 describedhereinafter, a white electromagnetic valve indicates a state in whichthe valve is opened by the control device, and a black electromagneticvalve indicates a state in which the valve is closed by the controldevice.

Moreover, the control device starts the operations of the air blower 22and the fans 27, 28, and drives the driving element of the compressor11. Accordingly, the low-pressure refrigerant is sucked and compressedby the first rotary compression element of the compressor 11 to indicatean intermediate pressure, and is discharged into the sealed container11A. The refrigerant discharged into the sealed container 11A is oncedischarged to the outside of the gas cooler 12 from the refrigerantintroducing tube 32, and enters the intermediate cooling circuit 150.Moreover, the refrigerant receives air flow by the air blower 22 of thegas cooler 12 while passing through the heat exchanger 152.

When the refrigerant compressed by the first rotary compression elementis cooled by the heat exchanger 152, and thereafter sucked by the secondrotary compression element, the temperature of the refrigerant gasdischarged from the second rotary compression element of the compressor11 can be lowered. Accordingly, since evaporation temperature of therefrigerant in the respective evaporators 17, 18 drops, the coolingchamber 2 and the storage chamber 3 can be cooled at lower temperature.Therefore, cooling capabilities of the cooling chamber 2 and the storagechamber 3 by the respective evaporators 17, 18 can be enhanced.

Thereafter, the refrigerant is sucked and compressed by the secondrotary compression element to constitute a high-temperature/pressurerefrigerant gas, and discharged to the outside of the compressor 11 fromthe refrigerant discharge tube 34. At this time, the refrigerant iscompressed to an appropriate supercritical pressure. The refrigerant gasdischarged from the compressor 11 flows into the gas cooler 12 from therefrigerant discharge tube 34.

Here, the high-temperature/pressure refrigerant compressed by thecompressor 11 does not condense, and operation is performed in asupercritical state. After the high-temperature/pressure refrigerant gasradiates heat by the gas cooler 12, the gas flows out of the gas cooler12, and enters the refrigerant pipe 36. The refrigerant which hasentered the refrigerant pipe 36 passes through the internal heatexchanger 45 as such without flowing through the first bypass circuit140, because the electromagnetic valve 170 is opened and theelectromagnetic valve 172 is closed as described above. The heat of therefrigerant is taken by the refrigerant flowing out of the evaporators17, 18 on the low-pressure side, and the refrigerant is further cooled.By the presence of the internal heat exchanger 45, the heat of therefrigerant flowing out of the gas cooler 12 and passing through theinternal heat exchanger 45 is taken by the refrigerant on thelow-pressure side, and therefore supercooling degree of the refrigerantincreases the more. Therefore, the cooling capabilities in therespective evaporators 17, 18 are enhanced.

The refrigerant cooled by the internal heat exchanger 45 on thehigh-pressure side reaches the expansion valve 16. It is to be notedthat the refrigerant still has a supercritical state in the inlet of theexpansion valve 16. The refrigerant is brought into a two-phase mixedstate of a gas/liquid by pressure drop in the expansion valve 16.Moreover, the refrigerant brought into the two-phase mixed state flowsinto the evaporator 17 disposed in the cooling chamber 2. There, therefrigerant evaporates, and absorbs the heat from ambient air to therebyexert a cooling function. It is to be noted that the air cooled by theevaporation of the refrigerant in the evaporator 17 is circulatedthrough the cooling chamber 2 by the operation of the fan 27 to cool theinside of the cooling chamber 2.

At this time, by an effect to cool the refrigerant compressed by thefirst rotary compression element by the heat exchanger 152 as describedabove, and an effect to pass the refrigerant flowing out of the gascooler 12 on the high-pressure side through the internal heat exchanger45 to cool the refrigerant, the refrigerant evaporates at lowertemperature by the evaporator 17. Accordingly, the cooling chamber 2 canbe cooled at lower temperature, and the cooling capability can beenhanced. Moreover, the refrigerant which has evaporated in theevaporator 17 thereafter flows out of the evaporator 17, and enters therefrigerant pipe 38.

On the other hand, the electromagnetic valve 65 is opened as describedabove, and therefore a part of the refrigerant whose pressure has beenreduced by the expansion valve 16 flows in the evaporator 18 installedin the storage chamber 3 from the second bypass circuit 42. Therefore,the refrigerant evaporates, and absorbs the heat from the ambient air tothereby exert a cooling function. The air cooled by the evaporation ofthe refrigerant in the evaporator 18 is circulated in the storagechamber 3 by the operation of the fan 28 to thereby cool the storagechamber 3.

Moreover, as described above, by the effect to cool the refrigerantcompressed by the first rotary compression element by the heat exchanger152, and the effect to pass the refrigerant which has flown out of thegas cooler 12 on the high-pressure side through the internal heatexchanger 45 to cool the refrigerant, the refrigerant evaporates atlower temperature in the evaporator 18. Accordingly, the inside of thestorage chamber 3 can be cooled at lower temperature, and the coolingcapability can be enhanced.

Moreover, the refrigerant which has flown out of the evaporator 18 flowstogether with the refrigerant flowing in the refrigerant pipe 38 fromthe evaporator 17, and reaches the internal heat exchanger 45.

There, the refrigerant takes the heat from the refrigerant on thehigh-pressure side, and is subjected to a heating function. Here, therefrigerant evaporates in the respective evaporators 17, 18 at the lowtemperature. The refrigerant which has flown out of the respectiveevaporators 17, 18 does not have a complete gas state, and the liquid issometimes mixed. However, when the refrigerant is passed through theinternal heat exchanger 45, and allowed to exchange the heat with thehigh-temperature refrigerant on the high-pressure side. Accordingly, therefrigerant is superheated, the superheating degree of the refrigerantis secured at this time, and the refrigerant completely turns to thegas.

Accordingly, the refrigerant which has flown out of the respectiveevaporators 17, 18 can be securely gasified. Therefore, withoutdisposing any accumulator or the like on the low-pressure side, suctionof liquid refrigerant into the compressor 11, that is, liquid backflowis securely prevented. A disadvantage that the compressor 11 is damagedby liquid compression can be avoided. Therefore, reliability of theheating/cooling system 100 can be enhanced.

It is to be noted that the refrigerant which has been heated by theinternal heat exchanger 45 repeats a cycle to be sucked into the firstrotary compression element of the compressor 11 from the refrigerantintroducing tube 30.

Thus, the air blower 22 is operated to radiate the heat from therefrigerant in the gas cooler 12, and the electromagnetic valve 172 isclosed to thereby interrupt the refrigerant circulation into theradiator 14. Accordingly, even when the radiator 14 and evaporator 18for heating/cooling the inside of the storage chamber 3 are disposed inthe storage chamber 3, the storage chamber 3 can be cooled without anytrouble.

(2) Mode in which Storage Chamber 3 is used as Heating Chamber

Next, a mode in which the storage chamber 3 is used as the heatingchamber for heating the articles will be described with reference toFIG. 3. FIG. 3 is a refrigerant circuit diagram showing a flow ofrefrigerant in this mode.

The electromagnetic valve 170 is closed by the control device (notshown), and the electromagnetic valve 172 is opened to thereby open thefirst bypass circuit 140. Accordingly, the refrigerant from the gascooler 12 does not flow in the internal heat exchanger 45 as such, andall flows in the first bypass circuit 140 from the middle portion of therefrigerant pipe 36.

Moreover, the control device closes the electromagnetic valve 65, andblocks the second bypass circuit 42. Accordingly, all the refrigerantfrom the expansion valve 16 flows in the evaporator 17. Furthermore, thecontrol device starts the operations of the fans 27, 28. At this time,it is assumed that the air blower 22 of the gas cooler 12 is notoperated.

Furthermore, when the driving element of the compressor 11 is driven bythe control device, the low-pressure refrigerant gas is sucked into thefirst rotary compression element (not shown) of the compressor 11 fromthe refrigerant introducing tube 30, compressed to indicate anintermediate pressure, and discharged into the sealed container 11A. Therefrigerant discharged into the sealed container 11A is once dischargedto the outside of the sealed container 11A from the refrigerantintroducing tube 32, enters the intermediate cooling circuit 150, andpasses through the heat exchanger 152. It is to be noted that in thepresent mode, the air blower 22 is not operated as described above.Therefore, the heat radiation of the refrigerant in the heat exchanger152 slightly or hardly occurs. Thus, when the air blower 22 is stopped,and the heat radiation in the heat exchanger 152 of the intermediatecooling circuit 150 is substantially invalidated, the refrigerant suckedinto the second rotary compression element can be held at hightemperature. Therefore, the refrigerant discharged from the compressor11 is at high temperature, and the heat can be conveyed to the radiator14. Accordingly, the heating capability in the radiator 14 can besecured.

Thereafter, the refrigerant is sucked into the second rotary compressionelement, compressed to form a high-temperature/pressure refrigerant gas,and discharged to the outside of the compressor 11 from the refrigerantdischarge tube 34. At this time, the refrigerant is compressed to anappropriate supercritical pressure. The refrigerant gas discharged fromthe compressor 11 passes through the gas cooler 12. Since the air blower22 is not operated as described above, the refrigerant in the gas cooler12 slightly or hardly radiates heat.

Since the electromagnetic valve 170 is closed, and the electromagneticvalve 172 is opened as described above, the refrigerant which has flownout of the gas cooler 12 enters the first bypass circuit 140 from therefrigerant pipe 36, and flows in the radiator 14 disposed in thestorage chamber 3. Here, the high-temperature/pressure refrigerantcompressed by the compressor 11 does not condense, and is operated in asupercritical state. Moreover, the high-temperature/pressure refrigerantgas radiates the heat in the radiator 14. It is to be noted that the airheated by the heat radiation of the refrigerant in the radiator 14 iscirculated in the storage chamber 3 by the operation of the fan 28 tothereby heat the inside of the storage chamber 3. In the presentinvention, since carbon dioxide is used as the refrigerant, therefrigerant does not condense in the radiator 14, therefore a heatexchange capability in the radiator 14 is remarkably high, and the airin the storage chamber 3 can be set at the high temperature.

Moreover, since the air blower 22 stops as described above, therefrigerant hardly radiates heat in the heat exchanger 152 and gascooler 12 of the intermediate cooling circuit 150, and the refrigerantmaintained at the high temperature can radiate the heat in the radiator14. Since the heat can be conveyed to the radiator 14 in this manner,the heating capability in the radiator 14 can be sufficiently secured.

Furthermore, since the refrigerant can be passed through the radiator 14before reaching the internal heat exchanger 45, the inside of thestorage chamber 3 can be heated by the refrigerant before thetemperature drops in the internal heat exchanger 45. Accordingly, theheating capability in the storage chamber 3 can be enhanced.

Therefore, the refrigerant enters the refrigerant pipe 36 on the outletside of the electromagnetic valve 170 from the first bypass circuit 140,and passes through the internal heat exchanger 45. The heat of therefrigerant is taken by the refrigerant which has flown out of theevaporator 17 on the low-pressure side, and is further cooled. Moreover,the refrigerant gas on the high-pressure side cooled by the internalheat exchanger 45 reaches the expansion valve 16. It is to be noted thatthe refrigerant gas still has the supercritical state in the inlet ofthe expansion valve 16. The refrigerant is brought into a mixed state oftwo phases of gas/liquid by the pressure drop in the expansion valve 16.Moreover, since the electromagnetic valve 65 is closed as describedabove, all the refrigerant that has flown out of the expansion valve 16flows in the evaporator 17 installed in the cooling chamber 2 withoutflowing through the second bypass circuit 42.

There, the refrigerant evaporates, and absorbs heat from the ambient airto thereby exert the cooling function. It is to be noted that the aircooled by the evaporation of the refrigerant in the evaporator 17 iscirculated in the cooling chamber 2 to thereby cool the inside of thecooling chamber 2 by the operation of the fan 27. Moreover, therefrigerant flows out of the evaporator 17, enters the refrigerant pipe38, and passes through the internal heat exchanger 45.

There, the refrigerant repeats a cycle of taking the heat from therefrigerant on the high-pressure side, receiving the heating function,and completely turning into the gas state to be sucked into the firstrotary compression element of the compressor 11 from the refrigerantintroducing tube 30.

Thus, the electromagnetic valve 65 is closed to thereby interrupt therefrigerant circulation into the evaporator 18, and the refrigerant isevaporated by the evaporator 17. Accordingly, even when the radiator 14and evaporator 18 for heating/cooling the inside of the storage chamber3 are disposed in the storage chamber 3, the storage chamber 3 can beheated without any trouble.

As described above in detail, when carbon dioxide having a satisfactoryheating characteristic is used as the refrigerant, the inside of thestorage chamber 3 is cooled by the evaporator 18, and the inside of thestorage chamber 3 can be heated by the refrigerant passed through thegas cooler 12 on the high-pressure side. Accordingly, the inside of thestorage chamber 3 can be heated without using any heating member such asan electric heater, and therefore power consumption can be saved ascompared with the heating by the electric heater.

Especially, in a case where the inside of the storage chamber 3 isheated by the evaporator 18, the air blower 22 is stopped, therefore theheat is conveyed to the evaporator 18 without radiating the heat fromthe refrigerant in the gas cooler 12, and the heating capability in thestorage chamber 3 can be enhanced.

Furthermore, in a case where the inside of the storage chamber 3 isheated by the evaporator 18, the heat radiation in the heat exchanger152 of the intermediate cooling circuit 150 is invalidated, the heat canbe conveyed to the evaporator 18 the more, and the heating capabilitycan be further enhanced.

Furthermore, when the opening/closing of the respective electromagneticvalves 170, 172, 65, and the operation of the air blower 22 arecontrolled, the heating/cooling in the storage chamber 3 can be freelyswitched. Accordingly, convenience of the heating/cooling system 100 canbe enhanced. Furthermore, even when the radiator 14 and evaporator 18for heating/cooling the inside of the storage chamber 3 are disposed inthe storage chamber 3 as in the present embodiment, the storage chamber3 can be heated/cooled without any trouble.

Moreover, when the gas cooler 12 is integrally formed with the heatexchanger 152 as in the present embodiment, an installation space can bereduced. Furthermore, since the air blower 22 of the gas cooler 12 canbe used also for the heat exchanger 152 by this constitution, productioncost can also be reduced.

It is to be noted that in the mode in which the storage chamber 3 of theabove-described embodiment is used as the heating chamber for heatingthe articles, the electric heater 80 disposed in the storage chamber 3may be operated to supplementarily perform the heating by the electricheater 80 in addition to the heating by the radiator 14. In this case,it is possible to avoid, in advance, a disadvantage that the storagechamber 3 cannot be sufficiently heated by shortage of the heatingcapability caused at low outside air temperature, for example, inwinter. Since the electric heater 80 supplements the heating by theradiator 14, the capacity of the electric heater 80 can be reduced, andtherefore the power consumption can be reduced as compared with theheating only by the electric heater.

Moreover, in the present embodiment, one storage chamber usable in sucha manner as to be switched to be hot/cold is disposed, but the presentinvention is not limited to this. Two or more storage chambers, aradiator and an evaporator for heating/cooling each storage chamber, andchannel control means for controlling refrigerant circulation may bedisposed, and the channel control means may be controlled in such amanner as to switch the heating/cooling of each storage chamber.

Furthermore, in the present embodiment, the radiator 14 and theevaporator 18 are disposed in the storage chamber 3, but the presentinvention is not limited to the embodiment. For example, a duct may bedisposed outside the storage chamber, the radiator and evaporator aredisposed in the duct, air blowing is switched by the air blower tothereby send hot or cold air to the storage chambers, and accordinglythe heating/cooling is switched. Even in this case, the presentinvention is effective.

It is to be noted that in the present embodiment, the internalintermediate pressure type two-stage compression system rotarycompressor is used, but the compressor usable in the present inventionis not limited to this compressor, and any compression form or stagenumber may be used.

Embodiment 2

Next, FIG. 4 is a schematic constitution diagram of a heating/coolingsystem 100 to which another invention has been applied. It is to benoted that this heating/cooling system of the present invention is alsousable in a showcase, an automatic vending machine, an air conditioner,a cold/hot storage or the like.

In FIG. 4, reference numeral 1 denotes a storage chamber of theheating/cooling system 100, and the storage chamber 1 is surrounded withan insulating member. A cooling chamber 2 and a storage chamber 5aredisposed in the storage chamber 1, and the storage chamber 5 can bedivided by an insulating material 7 which is a partition member in aninsulating manner.

The insulating material 7 is a partition member capable of dividing thestorage chamber 5 in an insulating manner, and is structured to bemovable. Moreover, when the storage chamber 5 is divided by theinsulating material 7 as shown in FIG. 4, a chamber 3 is formed in onestorage chamber 5 divided by the insulating material 7, and a chamber 4is formed in the other storage chamber 5 (on the right side of theinsulating material 7 in FIG. 4). In this case, the cooling chamber 2 isconnected to the chamber 3. That is, when the cooling chamber 2 and thechamber 3 are not divided by the insulating material 7 as describedlater, the cooling chamber 2 is not partitioned from the chamber 3 inthe insulating manner, and the chamber 3 is formed in such a manner asto communicate with the cooling chamber 2. Accordingly, cold air cooledin an evaporator 17 by a fan 27 disposed in the cooling chamber 2 asdescribed later is supplied to the chamber 3, and the chamber is cooledin the same manner as in the cooling chamber 2.

On the other hand, in a case where the storage chamber 5 is not dividedby the insulating material 7, and the cooling chamber 2 is divided fromthe storage chamber 5 as shown in FIG. 7, air heated in radiator 15 by afan 29 described later, or air cooled by an evaporator 19 is suppliedinto the storage chamber 5. Therefore, all spaces (chambers 3 and 4) inthe storage chamber 5 can be heated or cooled by the radiator 15 or theevaporator 19.

In the cooling chamber 2, the evaporator 17 for evaporating refrigerant,and the fan 27 for sending (circulating) air which has exchanged heatwith the evaporator 17 to the cooling chamber 2 are disposed. It is tobe noted that the evaporator 17 is disposed separately from theevaporator 19 described later.

Moreover, in a case where the storage chamber 5 is divided by theinsulating material 7, in the chamber 4 on the side which does notcommunicate with the cooling chamber 2, the radiator 15 for heating theinside of the chamber 4, an electric heater 81 which is an auxiliaryheater for heating the chamber 4, the evaporator 19 for cooling theinside of the chamber 4, and the fan 29 for sending (circulating) airwhich has exchanged heat with the radiator 15 or the evaporator 19, orair heated by the electric heater 81 into the chamber 4 are disposed.

On the other hand, in FIG. 4, reference numeral 10 denotes a refrigerantcircuit, and a compressor 11, a gas cooler 12, an expansion valve 16which is a pressure reducing device, the evaporator 17 and the like aresuccessively piped/connected in an annular shape to thereby constitutethe circuit.

That is, a refrigerant discharge tube 34 of the compressor 11 isconnected to an inlet of the gas cooler 12. Here, the compressor 11 ofthe present embodiment is an internal intermediate pressure typetwo-step compression system rotary compressor, and has a driving element(not shown), and first and second rotary compression elements (notshown) driven by this driving element in a sealed container 11A.

In the figure, reference numeral 30 denotes a refrigerant introducingtube for introducing the refrigerant to the first rotary compressionelement of the compressor 11, and one end of the refrigerant introducingtube 30 communicates with a cylinder of the first rotary compressionelement. The other end of the refrigerant introducing tube 30 isconnected to an outlet of an internal heat exchanger 45 described later.

In the figure, reference numeral 32 denotes a refrigerant introducingtube for introducing the refrigerant compressed by the first rotarycompression element to the second rotary compression element. Therefrigerant discharge tube 34 is a refrigerant pipe for discharging therefrigerant compressed by the second rotary compression element to thegas cooler 12.

A refrigerant pipe 36 connected to the outlet side of the gas cooler 12is connected to the internal heat exchanger 45. It is to be noted thatthe internal heat exchanger 45 exchanges heat between the refrigerant ona high-pressure side, and the refrigerant on a low-pressure side. Arefrigerant pipe 37 connected to the outlet of the internal heatexchanger 45 is connected to an inlet of the evaporator 17 of thecooling chamber 2 via the expansion valve 16.

Here, a first bypass circuit 40 is branched midway in the refrigerantdischarge tube 34. The first bypass circuit 40 is disposed in such amanner as to extend through the radiator 15 disposed in the storagechamber 4, and is connected to the refrigerant pipe 36. Moreover, thefirst bypass circuit 40 and the refrigerant discharge tube 34 areprovided with electromagnetic valves 70, 72 which are channel controlmeans for controlling refrigerant circulation with respect to the gascooler 12 and the radiator 15. It is to be noted that the refrigerantcirculation into the gas cooler 12 and radiator 15 is not limited tocontrol of the respective electromagnetic valves 70 and 72, and therefrigerant circulation into the gas cooler 12 and radiator 15 may becontrolled using and switching a three-way valve.

Moreover, a second bypass circuit 42 is branched from a middle portionof the refrigerant pipe 37 extending from the expansion valve 16. Thesecond bypass circuit 42 is disposed in such a manner as to pass throughthe evaporator 19 disposed in the chamber 4, and thereafter extendtogether with a refrigerant pipe 38 extending from the evaporator 17. Ina piping on the inlet side of the evaporator 19, an electromagneticvalve 65 is disposed as the channel control means for controlling therefrigerant circulation into the evaporator 19.

Here, as the refrigerant to be sealed in the refrigerant circuit 10,carbon dioxide (CO₂) which is ecological for global environment andwhich is natural refrigerant is used in consideration of combustibility,toxicity and the like.

Moreover, the above-described respective electromagnetic valves 65, 70,72 are controlled in such a manner as to open/close by control devices(not shown), respectively. It is to be noted that the control device iscontrol means for controlling the heating/cooling system 100, and inaddition to the respective electromagnetic valves 65, 70, 72, operationsof the compressor 11 and fans 22, 27, 29 and the like are alsocontrolled.

(1) Mode to use Chambers 3 and 4 as Cooling Chambers

Next, an operation of the heating/cooling system 100 constituted asdescribed above according to the present invention will be described.First, a mode to use the chambers 3 and 4 as the cooling chambers forcooling articles will be described with reference to FIG. 5. FIG. 5 is arefrigerant circuit diagram showing a flow of the refrigerant in thismode. When an operator attaches the insulating material 7 to the storagechamber 5, the inside of the storage chamber 5 is divided, the chamber 4is formed on the right side of the insulating material 7, and thechamber 3 is formed on the left side. In this case, the chamber 3 isstructured in such a manner as to communicate with the cooling chamber 2as described above.

Moreover, the electromagnetic valve 70 is opened, the electromagneticvalve 72 is closed, and the first bypass circuit 40 is blocked by thecontrol device (not shown). Accordingly, all the refrigerant dischargedfrom the compressor 11 flows through the gas cooler 12 from therefrigerant discharge tube 34. The control device opens theelectromagnetic valve 65 to open the second bypass circuit 42.Accordingly, the refrigerant from the expansion valve 16 flows into theevaporator 19. It is to be noted that in FIGS. 5 to 7 describedhereinafter, a white electromagnetic valve indicates a state in whichthe valve is opened by the control device, and a black electromagneticvalve indicates a state in which the valve is closed by the controldevice.

Moreover, the control device starts the operations of the fans 22, 27,29, and drives the driving element of the compressor 11. Accordingly,the low-pressure refrigerant is sucked and compressed by the firstrotary compression element of the compressor 11 to indicate anintermediate pressure, and is discharged into the sealed container 11A.The refrigerant discharged into the sealed container 11A is oncedischarged to the outside of the sealed container 11A from therefrigerant introducing tube 32, and is thereafter sucked and compressedin the second rotary compression element. Moreover, the refrigerantforms a high-temperature/pressure refrigerant gas, and is discharged tothe outside of the compressor 11 from the refrigerant discharge tube 34.At this time, the refrigerant is compressed to an optimum supercriticalpressure.

The refrigerant gas discharged from the compressor 11 flows into the gascooler 12 from the refrigerant discharge tube 34, because theelectromagnetic valve 70 is opened, and the electromagnetic valve 72 isclosed. Here, the high-temperature/pressure refrigerant compressed bythe compressor 11 does not condense, and operation is performed in asupercritical state. After the high-temperature/pressure refrigerant gasradiates heat in the gas cooler 12, the gas passes through the internalheat exchanger 45. The heat of the refrigerant is taken by therefrigerant flowing out of the evaporators 17, 19 on the low-pressureside, and the refrigerant is further cooled. By the presence of theinternal heat exchanger 45, the heat of the refrigerant flowing out ofthe gas cooler 12 and passing through the internal heat exchanger 45 istaken by the refrigerant on the low-pressure side, and thereforesupercooling degree of the refrigerant increases the more. Therefore,the cooling capabilities in the respective evaporators 17, 19 areenhanced.

The refrigerant gas cooled by the internal heat exchanger 45 on thehigh-pressure side reaches the expansion valve 16. It is to be notedthat the refrigerant gas still has a supercritical state in the inlet ofthe expansion valve 16. The refrigerant is brought into a two-phasemixed state of a gas/liquid by pressure drop in the expansion valve 16.Moreover, the refrigerant brought into the two-phase mixed state flowsinto the evaporator 17 disposed in the cooling chamber 2. There, therefrigerant evaporates, and absorbs the heat from ambient air to therebyexert a cooling function. It is to be noted that the air cooled by theevaporation of the refrigerant in the evaporator 17 is circulatedthrough the cooling chamber 2 and the chamber 3 communicating with thecooling chamber 2 by the operation of the fan 27 to thereby cool theinsides of the cooling chamber 2 and the chamber 3.

On the other hand, the electromagnetic valve 65 is opened as describedabove, and therefore a part of the refrigerant whose pressure has beenreduced by the expansion valve 16 enters the second bypass circuit 42branched/connected to the middle portion of the refrigerant pipe 37. Therefrigerant then flows in the evaporator 19 installed in the chamber 4,evaporates there, and absorbs the heat from the ambient air to therebyexert a cooling function. The air cooled by the evaporation of therefrigerant in the evaporator 19 is circulated in the chamber 4 by theoperation of the fan 29 to thereby cool the chamber 4.

Moreover, the refrigerant which has flown out of the evaporator 19 flowstogether with the refrigerant flowing in the refrigerant pipe 38 fromthe evaporator 17, and reaches the internal heat exchanger 45. There,the refrigerant takes the heat from the refrigerant on the high-pressureside, and is subjected to a heating function. Here, the refrigerantevaporates in the respective evaporators 17, 19 at the low temperature.The refrigerant which has flown out of the respective evaporators 17, 19does not have a complete gas state, and the liquid is sometimes mixed.However, when the refrigerant is passed through the internal heatexchanger 45, and allowed to exchange the heat with the high-temperaturerefrigerant on the high-pressure side. Accordingly, the refrigerant issuperheated, the superheating degree of the refrigerant is secured atthis time, and the refrigerant completely turns to the gas.

Accordingly, the refrigerant which has flown out of the respectiveevaporators 17, 19 can be securely gasified. Therefore, withoutdisposing any accumulator or the like on the low-pressure side, suctionof liquid refrigerant into the compressor 11, that is, liquid backflowis securely prevented. A disadvantage that the compressor 11 is damagedby liquid compression can be avoided. Therefore, reliability of theheating/cooling system 100 can be enhanced.

It is to be noted that the refrigerant which has been heated by theinternal heat exchanger 45 repeats a cycle to be sucked into the firstrotary compression element of the compressor 11 from the refrigerantintroducing tube 30.

Thus, the storage chamber 5 is comparted by the insulating material 7,and the accordingly formed chamber 3 is structured in such a manner asto communicate with the cooling chamber 2, so that the inside of thechamber 3 can be cooled by the evaporator 17 disposed in the coolingchamber 2. Moreover, the gas cooler 12 is disposed separately from theradiator 15 for heating the chamber 4, the heat is radiated from therefrigerant in the gas cooler 12, and accordingly the chamber 4 isusable as the cooling chamber for cooling the articles. Therefore, thechambers 3 and 4 can be cooled.

(2) Mode in which Chamber 3 is used as Cooling Chamber and Chamber 4 isused as Heating Chamber

Next, a mode in which the chamber 3 is used as the cooling chamber forcooling the articles, and the chamber 4 is used as the heating chamberfor heating the articles will be described with reference to FIG. 6.FIG. 6 is a refrigerant circuit diagram showing a flow of refrigerant inthis mode.

It is assumed that in this mode, the storage chamber 5 is comparted bythe insulating material 7 in the same manner as in the above-describedmode. Therefore, as described above, the chamber 3 is structured in sucha manner as to communicate with the cooling chamber 2. Theelectromagnetic valve 70 is closed by the control device (not shown),and the electromagnetic valve 72 is opened to thereby open the firstbypass circuit 40. Accordingly, the refrigerant discharged from thecompressor 11 does not flow in the gas cooler 12, and all flows in thefirst bypass circuit 40 from the middle portion of the refrigerantdischarge tube 34.

Moreover, the control device closes the electromagnetic valve 65, andblocks the second bypass circuit 42. Accordingly, all the refrigerantfrom the expansion valve 16 flows in the evaporator 17. Furthermore, thecontrol device starts the operations of the fans 22, 27, 29, and drivesthe driving element of the compressor 11. Accordingly, the low-pressurerefrigerant is sucked into the first rotary compression element of thecompressor 11, compressed to indicate an intermediate pressure, anddischarged into the sealed container 11A. The refrigerant dischargedinto the sealed container 11A is once discharged to the outside of thesealed container 11A from the refrigerant introducing tube 32, and isthereafter sucked and compressed by the second rotary compressionelement. Moreover, the refrigerant turns to thehigh-temperature/pressure refrigerant gas, and is discharged to theoutside of the compressor 11 from the refrigerant discharge tube 34. Atthis time, the refrigerant is compressed to optimum supercriticalpressure.

Since the electromagnetic valve 70 is closed, and the electromagneticvalve 72 is opened as described above, the refrigerant gas dischargedfrom the compressor 11 enters the first bypass circuit 40 from therefrigerant discharge tube 34, and flows in the radiator 15 disposed inthe chamber 4. Here, the high-temperature/pressure refrigerantcompressed by the compressor 11 does not condense, and is operated in asupercritical state. Moreover, the high-temperature/pressure refrigerantgas radiates the heat in the radiator 15. It is to be noted that the airheated by the heat radiation of the refrigerant in the radiator 15 iscirculated in the chamber 4 by the operation of the fan 29 to therebyheat the inside of the chamber 4. In the present invention, since carbondioxide is used as the refrigerant, the refrigerant does not condense inthe radiator 15, therefore a heat exchange capability in the radiator 15is remarkably high, and the air in the chamber 4 can be sufficiently setat the high temperature.

Thereafter, the refrigerant enters the refrigerant pipe 36 from thefirst bypass circuit 40, and passes through the internal heat exchanger45. The heat of the refrigerant is taken by the refrigerant which hasflown out of the evaporator 17 on the low-pressure side, and is furthercooled. Moreover, the refrigerant gas on the high-pressure side cooledby the internal heat exchanger 45 reaches the expansion valve 16. It isto be noted that the refrigerant gas still has the supercritical statein the inlet of the expansion valve 16. The refrigerant is brought intoa mixed state of two phases of gas/liquid by the pressure drop in theexpansion valve 16, and flows in the evaporator 17 disposed in thecooling chamber 2.

There, the refrigerant evaporates, and absorbs heat from the ambient airto thereby exert the cooling function. It is to be noted that the aircooled by the evaporation of the refrigerant in the evaporator 17 iscirculated in the cooling chamber 2 and the chamber 3 communicating withthe cooling chamber 2 to thereby cool the insides of the cooling chamber2 and chamber 3 by the operation of the fan 27. Moreover, therefrigerant flows out of the evaporator 17, enters the refrigerant pipe38, and passes through the internal heat exchanger 45.

There, the refrigerant repeats a cycle of taking the heat from therefrigerant on the high-pressure side, receiving the heating function,and completely turning into the gas state to be sucked into the firstrotary compression element of the compressor 11 from the refrigerantintroducing tube 30.

Thus, the storage chamber 5 is comparted by the insulating material 7,and the accordingly formed one chamber (chamber 3) is structured in sucha manner as to communicate with the cooling chamber 2, so that thechamber can be cooled by the evaporator 17 disposed in the coolingchamber 2, and the other chamber (chamber 4) can be heated by theradiator 15.

(3) Mode to use Chambers 3 and 4 as Heating Chambers

Next, an operation of the heating/cooling system 100 in a mode in whichthe chambers 3 and 4 are used as heating chambers for heating articleswill be described with reference to FIG. 7. FIG. 7 is a refrigerantcircuit diagram showing a flow of the refrigerant in this mode.

The operator removes the insulating material 7 for comparting thestorage chamber 5, and attaches the insulating material 7 between thecooling chamber 2 and the storage chamber 5. Accordingly, the coolingchamber 2 is comparted from the storage chamber 5 in an insulatingmanner. The chambers 3 and 4 are connected to thereby constitute onestorage chamber 5.

Moreover, the electromagnetic valve 70 is closed, the electromagneticvalve 72 is opened, and the first bypass circuit 40 is released by thecontrol device (not shown). Accordingly, all the refrigerant dischargedfrom the compressor 11 does not flow through the gas cooler 12, andflows in the first bypass circuit 40 from the middle portion of therefrigerant discharge tube 34.

Moreover, the control device closes the electromagnetic valve 65 toblock the second bypass circuit 42. Accordingly, the refrigerant fromthe expansion valve 16 flows into the evaporator 17. The control devicestarts the operations of the fans 22, 27, 29, and drives the drivingelement of the compressor 11. Accordingly, the low-pressure refrigerantis sucked and compressed by the first rotary compression element of thecompressor 11 to indicate an intermediate pressure, and is dischargedinto the sealed container 11A. The refrigerant discharged into thesealed container 11A is once discharged to the outside of the sealedcontainer 11A from the refrigerant introducing tube 32, and isthereafter sucked and compressed in the second rotary compressionelement. Moreover, the refrigerant forms a high-temperature/pressurerefrigerant gas, and is discharged to the outside of the compressor 11from the refrigerant discharge tube 34. At this time, the refrigerant iscompressed to an optimum supercritical pressure.

The refrigerant gas discharged from the compressor 11 flows into thefirst bypass circuit 40 from the refrigerant discharge tube 34, becausethe electromagnetic valve 70 is closed, and the electromagnetic valve 72is opened as described above. Here, the high-temperature/pressurerefrigerant compressed by the compressor 11 does not condense, andoperation is performed in a supercritical state. Moreover, thehigh-temperature/pressure refrigerant gas radiates heat in the radiator15. It is to be noted that the air heated by the heat radiation of therefrigerant in the radiator 15 is circulated in the storage chamber 5 toheat all the spaces in the storage chamber 5 by the operation of the fan29. Since carbon dioxide is used as the refrigerant in the presentinvention, the refrigerant does not condense in the radiator 15,therefore a heat exchange capability in the radiator 15 is remarkablyhigh, and the air in the storage chamber 5 can be sufficiently set athigh temperature.

Thereafter, the refrigerant enters the refrigerant pipe 36 from thefirst bypass circuit 40, and passes through the internal heat exchanger45. The heat of the refrigerant is taken by the refrigerant flowing outof the evaporator 17 on the low-pressure side, and the refrigerant isfurther cooled. Moreover, the refrigerant gas cooled by the internalheat exchanger 45 on the high-pressure side reaches the expansion valve16. It is to be noted that the refrigerant gas still has a supercriticalstate in the inlet of the expansion valve 16. The refrigerant is broughtinto a two-phase mixed state of a gas/liquid by pressure drop in theexpansion valve 16, and flows into the evaporator 17 disposed in thecooling chamber 2.

There, the refrigerant evaporates, and absorbs the heat from ambient airto thereby exert a cooling function. It is to be noted that the aircooled by the evaporation of the refrigerant in the evaporator 17 iscirculated through the cooling chamber 2 by the operation of the fan 27to thereby cool the inside of the cooling chamber 2. Moreover, therefrigerant flows out of the evaporator 17, enters the refrigerant pipe38, and passes through the internal heat exchanger 45.

There, the refrigerant repeats a cycle of taking the heat from therefrigerant on the high-pressure side, receiving the heating function,and completely turning into the gas state to be sucked into the firstrotary compression element of the compressor 11 from the refrigerantintroducing tube 30.

Thus, the cooling chamber 2 is partitioned off the storage chamber 5 bythe insulating material 7, and all the spaces in the storage chamber 5can be heated by the radiator 15.

As described above in detail, when carbon dioxide having a satisfactoryheating characteristic is used as the refrigerant, the inside of thestorage chamber 5 can be heated by the radiator 15, and cooled by theevaporator 19. Accordingly, the storage chamber 5 can be heated by therefrigerant circuit 10 without disposing any heating member such as anelectric heater or any special heating device. Accordingly, powerconsumption of the heating/cooling system 100 can be remarkably reduced.

Moreover, when the refrigerant circulation is controlled by therespective electromagnetic valves 65, 70, 72 as in the above-describedrespective modes, the storage chamber 5 is usable in such a manner as tobe switched to be hot/cold. Therefore, when the opening/closing of eachelectromagnetic valve is switched depending on a use situation, thestorage chamber 5 can be freely controlled to be hot/cold.

Furthermore, as in the above-described respective modes, the storagechamber 5 can be comparted into the chambers 3 and 4, or the coolingchamber 2 is partitioned off the storage chamber 5 by the insulatingmaterial 7. That is, since a ratio of a heating region heated by theradiator 14 to a cooling region cooled by the evaporator 19 can bechanged by the insulating material 7, convenience of the heating/coolingsystem 100 can be enhanced.

Additionally, when the insulating material 7 is attached to the storagechamber 5, the chamber 3 communicates with the cooling chamber 2, andthe chamber is cooled by the evaporator 17. When the insulating material7 is attached between the cooling chamber 2 and the storage chamber 5,the chamber is heated or cooled by the radiator 15 or the evaporator 19.Therefore, when the insulating material 7 is simply moved withoutdisposing any radiator or evaporator in the chamber 3, theheating/cooling can be freely switched. Accordingly, production cost ofthe heating/cooling system 100 can be reduced.

Embodiment 3

Next, another embodiment of a heating/cooling system of the presentinvention will be described with reference to FIGS. 8 to 11. FIG. 8 is aschematic constitution diagram of a heating/cooling system 300 in thepresent embodiment. It is to be noted that components denoted with thesame reference numerals as those of FIGS. 4 to 7 produce similareffects.

In FIG. 8, reference numeral 310 denotes a refrigerant circuit of thepresent embodiment, and a compressor 11, a gas cooler 12, an expansionvalve 16 which is a pressure reducing device, an evaporator 17 and thelike are successively piped/connected in an annular shape to therebyconstitute the circuit.

In the figure, reference numeral 150 denotes an intermediate coolingcircuit comprising a heat exchanger 152 for cooling the refrigerantcompressed by a first rotary compression element of the compressor 11,and thereafter allowing a second rotary compression element to suck therefrigerant. The heat exchanger 152 is formed integrally with the gascooler 12, and a fan 22 for passing air through the heat exchanger 152and the gas cooler 12 to radiate heat from the refrigerant is disposedin the vicinity of the heat exchanger 152 and the gas cooler 12.

Moreover, in the figure, reference numeral 140 denotes a first bypasscircuit branched from a middle portion of a refrigerant pipe 36connected to an outlet of the gas cooler 12, and this first bypasscircuit 140 is disposed in such a manner as to extend through a radiator15 disposed in a chamber 4, and connected to the refrigerant pipe 36 onthe outlet side of an electromagnetic valve 170 described later.

The electromagnetic valve 170 and another electromagnetic valve 172 aredisposed as channel control means for controlling refrigerantcirculation into the radiator 15 in a piping on a downstream side of abranch of the first bypass circuit 140 of the refrigerant pipe 36, andon the inlet side of the radiator 15 of the first bypass circuit 140.The electromagnetic valves 170 and 172 are controlled in such a manneras to open/close by a control device (not shown).

That is, the electromagnetic valve 170 is opened, the electromagneticvalve 172 is closed, and the first bypass circuit 140 is blocked by thecontrol device (not shown). Accordingly, the refrigerant which hasradiated the heat in the gas cooler 12 does not flow into the firstbypass circuit 140, and flows into an internal heat exchanger 45 assuch. On the other hand, when the control device closes theelectromagnetic valve 170, opens the electromagnetic valve 172, andreleases the first bypass circuit 140, the refrigerant that has radiatedthe heat in the gas cooler 12 flows into the radiator 15 from the firstbypass circuit 140.

(1) Mode to use Chambers 3 and 4 as Cooling Chambers

Next, an operation of the heating/cooling system 300 constituted asdescribed above according to the present invention will be described.First, a mode to use the chambers 3 and 4 as the cooling chambers forcooling articles will be described with reference to FIG. 9. FIG. 9 is arefrigerant circuit diagram showing a flow of the refrigerant in thismode. When an operator attaches the insulating material 7 to the storagechamber 5, the inside of the storage chamber 5 is comparted, the chamber4 is formed on the right side of the insulating material 7, and thechamber 3 is formed on the left side. In this case, the chamber 3 isstructured in such a manner as to communicate with the cooling chamber 2as described above.

Moreover, the electromagnetic valve 70 is opened, the electromagneticvalve 72 is closed, and the first bypass circuit 40 is blocked by thecontrol device (not shown). Accordingly, the refrigerant from the gascooler 12 does not flow in the first bypass circuit 140, and flowsthrough the internal heat exchanger 45 as such. The control device opensthe electromagnetic valve 65 to open the second bypass circuit 42.Accordingly, the refrigerant from the expansion valve 16 flows into theevaporator 19. It is to be noted that in FIGS. 9 to 11 describedhereinafter, a white electromagnetic valve indicates a state in whichthe valve is opened by the control device, and a black electromagneticvalve indicates a state in which the valve is closed by the controldevice.

Moreover, the control device starts the operations of the fans 22, 27,29, and drives the driving element of the compressor 11. Accordingly,the low-pressure refrigerant gas is sucked and compressed by the firstrotary compression element (not shown) of the compressor 11 from therefrigerant introducing tube 30 to indicate an intermediate pressure,and is discharged into the sealed container 11A. The refrigerantdischarged into the sealed container 11A is once discharged to theoutside of the sealed container 11A from the refrigerant introducingtube 32, and thereafter enters the intermediate cooling circuit 150, andpasses through the heat exchanger 152. There, the refrigerant radiatesheat by the air passing by the fan 22.

Thus, the refrigerant compressed by the first rotary compression elementis cooled by the heat exchanger 152, and thereafter sucked into thesecond rotary compression element, so that the temperature of therefrigerant gas discharged from the second rotary compression element ofthe compressor 11 can be lowered. Accordingly, since evaporationtemperature of the refrigerant in the respective evaporators 17, 19drop, the cooling chamber 2 and the respective chambers 3, 4 can becooled at lower temperature. Therefore, cooling capabilities of thecooling chamber 2, and the chambers 3, 4 by the respective evaporators17, 19 can be enhanced.

Thereafter, the refrigerant is sucked and compressed by the secondrotary compression element to form a high-temperature/pressurerefrigerant gas, and the gas is discharged to the outside of thecompressor 11 from the refrigerant discharge tube 34. At this time, therefrigerant is compressed to the appropriate supercritical pressure. Therefrigerant gas discharged from the compressor 11 flows in the gascooler 12. Here, the refrigerant does not condense, and radiates theheat as such in the supercritical state.

Moreover, the refrigerant which has radiated the heat in the gas cooler12 passes through the intermediate cooling circuit 150 as such. There,the heat of the refrigerant is taken by the refrigerant which has flownout of the evaporators 17, 19 on the low-pressure side, and is furthercooled. By the presence of the internal heat exchanger 45, the heat ofthe refrigerant which has flown out of the gas cooler 12 and passedthrough the internal heat exchanger 45 is taken by the refrigerant onthe low-pressure side, and therefore supercooling degree of therefrigerant increases. Therefore, the cooling capabilities in theevaporators 17, 19 are enhanced.

The refrigerant gas cooled by the internal heat exchanger 45 on thehigh-pressure side reaches the expansion valve 16. It is to be notedthat the refrigerant gas still has a supercritical state in the inlet ofthe expansion valve 16. The refrigerant is brought into a two-phasemixed state of a gas/liquid by pressure drop in the expansion valve 16.Moreover, the refrigerant brought into the two-phase mixed state flowsinto the evaporator 17 disposed in the cooling chamber 2. There, therefrigerant evaporates, and absorbs the heat from ambient air to therebyexert a cooling function. It is to be noted that the air cooled by theevaporation of the refrigerant in the evaporator 17 is circulatedthrough the cooling chamber 2 and the chamber 3 communicating with thecooling chamber 2 by the operation of the fan 27 to thereby cool theinsides of the cooling chamber 2 and the chamber 3.

Moreover, by an effect to cool the refrigerant compressed by the firstrotary compression element by the heat exchanger 152 as described above,and an effect to pass the refrigerant discharged from the gas cooler 12on the high-pressure side through the internal heat exchanger 45 to coolthe refrigerant, the refrigerant evaporates at lower temperature by theevaporator 17. Accordingly, the cooling chamber 2 and the chamber 3 canbe cooled at lower temperature, and the cooling capability can beenhanced. Moreover, the refrigerant which has evaporated in theevaporator 17 thereafter flows out of the evaporator 17, and enters therefrigerant pipe 38.

On the other hand, the electromagnetic valve 65 is opened as describedabove, and therefore a part of the refrigerant whose pressure has beenreduced by the expansion valve 16 flows in the evaporator 19 installedin the storage chamber 4 from the second bypass circuit 42. Therefore,the refrigerant evaporates, and absorbs the heat from the ambient air tothereby exert a cooling function. The air cooled by the evaporation ofthe refrigerant in the evaporator 19 is circulated in the chamber 4 bythe operation of the fan 29 to thereby cool the chamber 4.

Moreover, as described above, by the effect to cool the refrigerantcompressed by the first rotary compression element by the heat exchanger152, and the effect to pass the refrigerant discharged from the gascooler 12 on the high-pressure side through the internal heat exchanger50 to cool the refrigerant, the refrigerant evaporates at lowertemperature in the evaporator 19. Accordingly, the inside of the chamber4 can be cooled at lower temperature, and the cooling capability can beenhanced.

Moreover, the refrigerant which has flown out of the evaporator 19 flowstogether with the refrigerant flowing in the refrigerant pipe 38 fromthe evaporator 17, and reaches the internal heat exchanger 45.

There, the refrigerant takes the heat from the refrigerant on thehigh-pressure side, and is subjected to a heating function. Here, therefrigerant evaporates in the respective evaporators 17, 19 at the lowtemperature. The refrigerant which has flown out of the respectiveevaporators 17, 19 does not have a complete gas state, and the liquid issometimes mixed. However, when the refrigerant is passed through theinternal heat exchanger 45, and allowed to exchange the heat with thehigh-temperature refrigerant on the high-pressure side. Accordingly, therefrigerant is superheated, the superheating degree of the refrigerantis secured at this time, and the refrigerant completely turns to thegas.

Accordingly, the refrigerant which has flown out of the respectiveevaporators 17, 19 can be securely gasified. Therefore, withoutdisposing any accumulator or the like on the low-pressure side, suctionof liquid refrigerant into the compressor 11, that is, liquid backflowis securely prevented. A disadvantage that the compressor 11 is damagedby liquid compression can be avoided. Therefore, reliability of theheating/cooling system 300 can be enhanced.

It is to be noted that the refrigerant which has been heated by theinternal heat exchanger 45 repeats a cycle to be sucked into the firstrotary compression element of the compressor 11 from the refrigerantintroducing tube 30.

Thus, the inside of the storage chamber 5 is comparted by the,insulating material 7, and the accordingly formed chamber 3 isstructured in such a manner as to communicate with the cooling chamber2, so that the inside of the chamber 3 can be cooled by the evaporator17 disposed in the cooling chamber 2. The gas cooler 12 is disposedseparately from the radiator 15 for heating the chamber 4, and the heatis radiated from the refrigerant in the gas cooler 12, so that thechamber 4 can be used as a cooling chamber for cooling articles.

(2) Mode in which Chamber 3 is used as Cooling Chamber and Chamber 4 isused as Heating Chamber

Next, an operation of the heating/cooling system 300 in a mode in whichthe chamber 3 is used as the cooling chamber for cooling the articles,and the chamber 4 is used as the heating chamber for heating thearticles will be described with reference to FIG. 10. FIG. 10 is arefrigerant circuit diagram showing a flow of refrigerant in this mode.

It is assumed that in this mode, the storage chamber 5 is comparted bythe insulating material 7 in the same manner as in the above-describedmode. Therefore, as described above, the chamber 3 is structured in sucha manner as to communicate with the cooling chamber 2. Theelectromagnetic valve 170 is closed by the control device (not shown),and the electromagnetic valve 172 is opened to thereby open the firstbypass circuit 140. Accordingly, all the refrigerant from the gas cooler12 flows in the first bypass circuit 140 from the middle portion of therefrigerant discharge tube 36.

Moreover, the control device closes the electromagnetic valve 65, andblocks the second bypass circuit 42. Accordingly, all the refrigerantfrom the expansion valve 16 flows in the evaporator 17. Furthermore, thecontrol device starts the operations of the fans 27, 29, and drives thedriving element of the compressor 11. Accordingly, the low-pressurerefrigerant gas is sucked into the first rotary compression element (notshown) of the compressor 11 from the refrigerant introducing tube 30,compressed to indicate an intermediate pressure, and discharged into thesealed container 11A. The refrigerant discharged into the sealedcontainer 11A is once discharged to the outside of the sealed container11A from the refrigerant introducing tube 32, enters the intermediatecooling circuit 150, and passes through the heat exchanger 152. It is tobe noted that since the fan 22 is not operated in the present mode, theheat radiation of the refrigerant in the heat exchanger 152 slightly orhardly occurs. Accordingly, the refrigerant sucked into the secondrotary compression element can be maintained at high temperature.Therefore, the refrigerant discharged from the compressor 11 is also athigh temperature, and ambient air can be heated at high temperature inthe radiator 15, so that a heating capability in the radiator 15 can besecured.

Thereafter, the refrigerant is sucked and compressed by the secondrotary compression element to constitute a high-temperature/pressurerefrigerant gas, and discharged to the outside of the compressor 11 fromthe refrigerant discharge tube 34. At this time, the refrigerant iscompressed to an appropriate supercritical pressure. The refrigerant gasdischarged from the compressor 11 passes through the gas cooler 12.Since the fan 22 is not operated as described above, the refrigerant inthe gas cooler 12 slightly or hardly radiates heat.

Since the electromagnetic valve 170 is closed, and the electromagneticvalve 172 is opened as described above, the refrigerant which has flownout of the gas cooler 12 enters the first bypass circuit 140 from therefrigerant pipe 36, and flows in the radiator 15 disposed in thechamber 4. Here, the high-temperature/pressure refrigerant compressed bythe compressor 11 does not condense, and is operated in a supercriticalstate. Moreover, the high-temperature/pressure refrigerant gas radiatesthe heat in the radiator 15. It is to be noted that the air heated bythe heat radiation of the refrigerant in the radiator 15 is circulatedin the chamber 4 by the operation of the fan 29 to thereby heat theinside of the chamber 4. In the present invention, since carbon dioxideis used as the refrigerant, the refrigerant does not condense in theradiator 15, therefore a heat exchange capability in the radiator 15 isremarkably high, and the air in the chamber 4 can be set at the hightemperature.

Moreover, since the fan 22 is not operated as described above, therefrigerant hardly radiates heat in the heat exchanger 152 and gascooler 12 of the intermediate cooling circuit 150, and the refrigerantmaintained at the high temperature can radiate the heat in the radiator15. Accordingly, the heating capability in the radiator 15 can besufficiently secured.

Thereafter, the refrigerant enters the refrigerant pipe 36 on the outletside of the electromagnetic valve 170 from the first bypass circuit 140,and passes through the internal heat exchanger 45. The heat of therefrigerant is taken by the refrigerant which has flown out of theevaporator 17 on the low-pressure side, and is further cooled. Moreover,the refrigerant gas on the high-pressure side cooled by the internalheat exchanger 45 reaches the expansion valve 16. It is to be noted thatthe refrigerant gas still has the supercritical state in the inlet ofthe expansion valve 16. The refrigerant is brought into a mixed state oftwo phases of gas/liquid by the pressure drop in the expansion valve 16,and flows into the evaporator 17 disposed in the cooling chamber 2.

There, the refrigerant evaporates, and absorbs heat from the ambient airto thereby exert the cooling function. It is to be noted that the aircooled by the evaporation of the refrigerant in the evaporator 17 iscirculated in the cooling chamber 2 and the chamber 3 communicating withthe cooling chamber 2 to thereby cool the insides of the cooling chamber2 and the chamber 3 by the operation of the fan 27. Moreover, therefrigerant flows out of the evaporator 17, enters the refrigerant pipe38, and passes through the internal heat exchanger 45.

There, the refrigerant repeats a cycle of taking the heat from therefrigerant on the high-pressure side, receiving the heating function,and completely turning into the gas state to be sucked into the firstrotary compression element of the compressor 11 from the refrigerantintroducing tube 30.

Thus, the inside of the storage chamber 5 is comparted by the insulatingmaterial 7, and one chamber (chamber 3) formed by comparting the chamberby the insulating material 7 is structured in such a manner as tocommunicate with the cooling chamber 2, so that the chamber is cooled bythe evaporator 17 disposed in the cooling chamber 2, and the otherchamber (chamber 4) can be heated by the radiator 15.

(3) Mode to use Chambers 3 and 4 as Heating Chambers

Next, an operation of the heating/cooling system 300 in a mode in whichthe chambers 3 and 4 are used as heating chambers for heating articleswill be described with reference to FIG. 11. FIG. 11 is a refrigerantcircuit diagram showing a flow of the refrigerant in this mode.

The operator removes the insulating material 7 for comparting thestorage chamber 5, and attaches the insulating material 7 between thecooling chamber 2 and the storage chamber 5. Accordingly, the coolingchamber 2 is comparted from the storage chamber 5 in an insulatingmanner. The chambers 3 and 4 are connected to thereby constitute onestorage chamber 5.

Moreover, the electromagnetic valve 170 is closed, the electromagneticvalve 172 is opened, and the first bypass circuit 140 is released by thecontrol device (not shown). Accordingly, all the refrigerant that hasflown from the gas cooler 12 flows in the first bypass circuit 140 fromthe middle portion of the refrigerant pipe 36.

Moreover, the control device closes the electromagnetic valve 65 toblock the second bypass circuit 42. Accordingly, all the refrigerantfrom the expansion valve 16 flows into the evaporator 17. The controldevice starts the operations of the fans 27, 29, and drives the drivingelement of the compressor 11. Accordingly, the low-pressure refrigerantgas is sucked and compressed by the first rotary compression element(not shown) of the compressor 11 to indicate an intermediate pressure,and is discharged into the sealed container 11A. The refrigerantdischarged into the sealed container 11A is once discharged to theoutside of the sealed container 11A from the refrigerant introducingtube 32, thereafter enters the intermediate cooling circuit 150, andpasses through the heat exchanger 152. It is to be noted that since thefan 22 is not operated in the present mode, the heat radiation of therefrigerant in the heat exchanger 152 slightly or hardly occurs.Accordingly, the refrigerant sucked into the second rotary compressionelement can be held at high temperature. Therefore, the refrigerantdischarged from the compressor 11 is at high temperature, the ambientair can be heated in the radiator 15, and accordingly the heatingcapability in the radiator 15 can be secured.

Thereafter, the refrigerant is sucked into the second rotary compressionelement, compressed to form a high-temperature/pressure refrigerant gas,and discharged to the outside of the compressor 11 from the refrigerantdischarge tube 34. At this time, the refrigerant is compressed to anappropriate supercritical pressure. The refrigerant gas discharged fromthe compressor 11 passes through the gas cooler 12. Since the fan 22 isnot operated as described above, the refrigerant in the gas cooler 12slightly or hardly radiates heat. Moreover, since the electromagneticvalve 170 is closed, and the electromagnetic valve 172 is opened asdescribed above, the refrigerant which has flown out of the gas cooler12 enters the first bypass circuit 140 from the refrigerant pipe 36, andflows in the radiator 15. Here, the high-temperature/pressurerefrigerant compressed by the compressor 11 does not condense, and isoperated in a supercritical state. Moreover, thehigh-temperature/pressure refrigerant gas radiates the heat in theradiator 15. It is to be noted that the air heated by the heat radiationof the refrigerant in the radiator 15 is circulated in the storagechamber 5 by the operation of the fan 29 to thereby heat the inside ofthe storage chamber 5. In the present invention, since carbon dioxide isused as the refrigerant, the refrigerant does not condense in theradiator 15, therefore a heat exchange capability in the radiator 15 isremarkably high, and the air in the storage chamber 5 can be set at thehigh temperature.

Moreover, since the fan 22 is not operated as described above, therefrigerant hardly radiates heat in the heat exchanger 152 and gascooler 12 of the intermediate cooling circuit 150, and the refrigerantmaintained at the high temperature can radiate the heat in the radiator15. Accordingly, the heating capability in the radiator 15 can besufficiently secured.

Furthermore, the refrigerant enters the refrigerant pipe 36 on theoutlet side of the electromagnetic valve 170 from the first bypasscircuit 140, and passes through the internal heat exchanger 45. The heatof the refrigerant is taken by the refrigerant which has flown out ofthe evaporator 17 on the low-pressure side, and is further cooled.Moreover, the refrigerant gas on the high-pressure side cooled by theinternal heat exchanger 45 reaches the expansion valve 16. It is to benoted that the refrigerant gas still has the supercritical state in theinlet of the expansion valve 16. The refrigerant is brought into a mixedstate of two phases of gas/liquid by the pressure drop in the expansionvalve 16, and flows in the evaporator 17 installed in the coolingchamber 2.

There, the refrigerant evaporates, and absorbs heat from the ambient airto thereby exert the cooling function. It is to be noted that the aircooled by the evaporation of the refrigerant in the evaporator 17 iscirculated in the cooling chamber 2 to thereby cool the inside of thecooling chamber 2 by the operation of the fan 27. Moreover, therefrigerant flows out of the evaporator 17, enters the refrigerant pipe38, and passes through the internal heat exchanger 45.

There, the refrigerant repeats a cycle of taking the heat from therefrigerant on the high-pressure side, receiving the heating function,and completely turning into the gas state to be sucked into the firstrotary compression element of the compressor 11 from the refrigerantintroducing tube 30.

Thus, when the cooling chamber 2 is partitioned off the storage chamber5 by the insulating material 7, all the spaces in the storage chamber 5can be heated by the radiator 15.

As described above in detail, also in the present embodiment, the insideof the storage chamber 5 can be heated by the radiator 15, and cooled bythe evaporator 19 in the same manner as in the above-describedembodiment. Accordingly, power consumption of the heating/cooling system300 can be remarkably reduced.

Further in the present embodiment, the intermediate cooling circuit 150.the heat exchanger 152 for radiating the heat from the refrigerantcompressed by the first rotary compression element, and the fan 22 forsupplying air through the heat exchanger 152 and gas cooler 12 aredisposed to thereby control the operation of the fan 22 as in theabove-described respective modes. Accordingly, enhancement of thecooling capability, and maintenance of the heating capability can berealized. Accordingly, the performance of the heating/cooling system 300can further be enhanced.

Moreover, when the gas cooler 12 is integrally formed with the heatexchanger 152 as in the present embodiment, an installation space can bereduced. Furthermore, since one fan 22 can be used in common, productioncost can also be reduced.

It is to be noted that in the present embodiment, the gas cooler 12 isformed integrally with the heat exchanger 152 as described above, andthe fan 22 is used in common, but the present invention is not limitedto this embodiment. The gas cooler 12 may be disposed separately fromthe heat exchanger 152, and the fan may be disposed in the vicinity ofthe both.

It is to be noted that in the mode in which the chamber 4 or the wholestorage chamber 5 of the above-described embodiment is used as theheating chamber for heating the articles, the electric heater 81disposed in the chamber 4 may be operated to supplementarily perform theheating by the electric heater 81 in addition to the heating by theradiator 15. In this case, it is possible to avoid, in advance, adisadvantage that the chamber 4 or the storage chamber 5 cannot besufficiently heated by shortage of the heating capability caused, forexample, in winter. Since the electric heater 81 supplements the heatingby the radiator 15, the capacity of the electric heater 81 can bereduced, and therefore the power consumption can be reduced as comparedwith the heating only by the electric heater.

Moreover, in the present embodiment, one storage chamber 5 ispartitioned by the insulating material 7 to thereby form two chambers(chambers 3, 4) usable in such a manner as to be switched to behot/cold, but the present invention is not limited to this. For example,three or more storage chambers are disposed, a radiator and anevaporator are disposed in the chambers excluding at least one storagechamber, the storage chamber in which any radiator or evaporator is notdisposed communicates with the other storage chambers in such a mannerthat the chamber can be partitioned, and the chambers can be used insuch a manner as to be switched to be hot/cold.

Embodiment 4

Next, another embodiment of a heating/cooling system of the presentinvention will be described. FIG. 12 is a refrigerant circuit diagram ina case where the heating/cooling system of the present invention isapplied to an open showcase 200, and FIGS. 13 to 16 show longitudinalside views of the open showcase 200. It is to be noted that in FIGS. 12to 16, components denoted with the same reference numerals as those ofFIGS. 4 to 11 produce similar effects.

The open showcase 200 of the present embodiment is a vertical type openshowcase installed in shops such as a supermarket, and comprises aninsulated wall 211 whose section substantially has a U-shape, and sideplates (not shown) attached to opposite sides of the insulated wall.Inside the insulated wall 211, a partition plate 212 is attached, a duct213 is formed between the insulated wall 211 and the partition plate212, and the inside of the partition plate 212 is constituted as astorage chamber 1.

In the storage chamber 1, a plurality of stages (four stages in theembodiment) of shelves which are partition members are disposed, andspaces on shelves 214, 215, 216, 217 are constituted as storage chambers270, 271, 272 for storing articles, and a chamber 273. Electric heaters80, 81, 82, 83 for heating the respective storage chambers 270, 271, 272and the chamber 273 are attached onto the respective shelves 214, 215,216, 217. The electric heaters 80, 81, 82 are disposed in such a manneras to compensate for shortage of the capability of the radiator 14because of the heating as described later. It is to be noted that theelectric heater 83 is disposed in such a manner as to heat the chamber273.

Suction ports 230, 232 (not shown in FIG. 12) are formed in upper andlower edges of a front face opening of the storage chamber 1, thesuction port 230 is connected to an upper duct 220 described later, andthe suction port 232 is connected to a bottom duct 219 described later.

On the other hand, a deck pan (not shown) is attached to a bottom partof the storage chamber 1, the bottom duct 219 connected to the duct 213is constituted below the deck pan, and an evaporator 17 and a fan 27 forcooling the respective storage chambers 270, 271, 272, and the chamber273 are disposed in the bottom duct 219. Moreover, holes 234, 234vertically extending through the chamber 273 and the bottom duct 219 areformed in the deck pan in such a manner that the air which has exchangedthe heat with the evaporator 17 is sent into the chamber 273 by the fan27.

On the other hand, the upper duct 220 is similarly formed in such amanner as to communicate with the duct 213 in an upper part of thestorage chamber 1. A radiator 14 and a fan 24 for heating the respectivestorage chambers 270, 271, 272 are disposed in the upper duct 220.Vertically extending through-holes 236 are formed in the storage chamber270 and the upper duct 220 in such a manner that the air which hasexchanged the heat with the evaporator 14 is sent into the chamber 270from the holes 236, 236 by the fan 24.

Furthermore, communication holes 237, 238, 239, 240 for connecting theduct 213 to the storage chambers 270, 271, 272 and the chamber 273 areformed in the partition plate 212, and the air which has exchanged theheat with the evaporator 14 is sent into the respective storage chambers270, 271, 272 and the chamber 273 from the respective communicationpaths 237, 238, 239, 240 via the duct 213 by the respective fans 27, 24.

Here, the shelves 214, 215, 216 may extend through the duct 213 in sucha manner as to vertically partition the duct 213 in an insulatingmanner. That is, holes (not shown) are formed in back surfaces (on theside of the duct 213 in FIGS. 13 to 16) of the respective shelves 214,215, 216 in such a manner that the respective shelves 214, 215, 216 canbe inserted in the duct 213. When the shelf 214, 215, or 216 is insertedin the duct 213 through the hole, each flow of air in the duct 213 canbe interrupted. Therefore, one chamber (upper side) partitioned by theshelf 214, 215, or 216 can be heated by the radiator 14, and the otherchamber (lower side) can be cooled by the evaporator 17.

On the other hand, a machine chamber 280 is formed under the bottom duct219, and a compressor 11, a gas cooler 12, an internal heat exchanger45, an expansion valve 16 which is a pressure reducing device and thelike, constituting a part of a refrigerant circuit 210 described later,are stored in the machine chamber 280. It is to be noted that thecompressor 11 for use in the present embodiment is a two-stagecompression system compressor, and comprises a driving element, andfirst and second compression elements driven by the driving element. Thegas cooler 12 radiates heat from a high-temperature/pressure refrigerantdischarged from the compressor 11, and a fan 22 is disposed in thevicinity of the gas cooler 12.

Here, the refrigerant circuit 210 will be described with reference toFIG. 12. The refrigerant circuit 210 is constituted by piping/connectingthe compressor 11, gas cooler 12, expansion valve 16, evaporator 17 andthe like in an annular shape. That is, a refrigerant discharge tube 34of the compressor 11 is connected to an inlet of the gas cooler 12. Arefrigerant pipe 36 connected to the outlet side of the gas cooler 12extends through the internal heat exchanger 45. It is to be noted thatthe internal heat exchanger 45 exchanges heat between the refrigerant ona high-pressure side, and the refrigerant on a low-pressure side. Arefrigerant pipe 37 connected to the outlet of the internal heatexchanger 45 is connected to an inlet of the evaporator 17 disposed inthe bottom duct 219 via the expansion valve 16. A refrigerant pipe 38extending from the evaporator 17 extends through the internal heatexchanger 45, and is connected to a refrigerant introducing tube 30. Itis to be noted that the refrigerant introducing tube 30 is connected toa first compression element of the compressor 11 in such a manner that alow-pressure refrigerant is sucked into the compressor 11.

Moreover, in FIG. 12, reference numeral 32 denotes a refrigerantintroducing tube for introducing the refrigerant compressed by the firstrotary compression element of the compressor 11 to the second rotarycompression element. The refrigerant introducing tube 32 is disposed insuch a manner as to extend through an intermediate cooling circuit 150disposed outside a sealed container. The intermediate cooling circuit150 is provided with a heat exchanger 152 for cooling the refrigerantcompressed by the first compression element, and the heat exchanger 152is constituted integrally with the gas cooler 12.

Here, a first bypass circuit 40 is branched from a middle portion of therefrigerant discharge tube 34, and an outlet of the first bypass circuit40 is connected to the middle portion of the refrigerant pipe 36. Thefirst bypass circuit 40 is disposed in such a manner as to extendthrough the radiator 14 disposed in the upper duct 220. On the inletside of the radiator 14 of the first bypass circuit 40, and in therefrigerant discharge tube 34, electromagnetic valves 70, 72 aredisposed as channel control means for controlling the refrigerant on thehigh-pressure side compressed by the second compression element of thecompressor 11 in such a manner as to be passed through the gas cooler 12or the first bypass circuit 40 from the refrigerant discharge tube 34.The valves are controlled to open/close by a control device (not shown).

It is to be noted that carbon dioxide is sealed as refrigerant in therefrigerant circuit 210, and the refrigerant circuit 210 has asupercritical pressure on the high-pressure side.

(1) Mode to use Storage Chambers 270, 271, 272 and Chamber 273

Next, an operation of the open showcase 200 constituted as describedabove will be described. First, the operation in a mode to use thestorage chambers 270, 271, 272 and chamber 273 as the cooling chambersfor cooling articles will be described with reference to FIG. 13.

It is to be noted that in this mode the shelf 214, 215, or 216 is notinserted in the duct 213. The electromagnetic valve 70 is opened, theelectromagnetic valve 72 is closed, and the first bypass circuit 40 isblocked by the control device (not shown). Accordingly, all therefrigerant discharged from the compressor 11 flows in the gas cooler 12from the refrigerant discharge tube 34 without flowing in the firstbypass circuit 40. It is to be noted that in FIGS. 13 to 16 describedhereinafter, a white electromagnetic valve indicates a state in whichthe valve is opened by the control device, and a black electromagneticvalve indicates a state in which the valve is closed by the controldevice.

Moreover, the control device starts the operations of the machinechamber 280, and the fans 22, 27, 24 stored in the bottom duct 219 andupper duct 220, and drives the driving element of the compressor 11.Accordingly, the low-pressure refrigerant gas is sucked and compressedby the first compression element (not shown) of the compressor 11 fromthe refrigerant introducing tube 30 to indicate an intermediatepressure, once discharged to the outside of the sealed container fromthe refrigerant introducing tube 32, and enters the intermediate coolingcircuit 150, and passes through the heat exchanger 152 disposed in thecircuit. Moreover, the refrigerant is subjected to air passing by thefan 22, and radiates heat while passing through the heat exchanger 152,constitutes a high-temperature/pressure refrigerant gas, and isdischarged to the outside of the compressor 11 from the refrigerantdischarge tube 34. At this time, the refrigerant is compressed to anoptimum supercritical pressure. The refrigerant gas discharged from thecompressor 11 flows into the gas cooler 12 from the refrigerantdischarge tube 34, because the electromagnetic valve 70 is opened, andthe electromagnetic valve 72 is closed. Here, thehigh-temperature/pressure refrigerant compressed by the compressor 11does not condense, and operation is performed in a supercritical state.Moreover, the high-temperature/pressure refrigerant gas receives the airpassing by the fan 22 to radiate the heat. Since carbon dioxide is usedas the refrigerant in the present invention, the refrigerant does notcondense in the gas cooler 12, flows out of the gas cooler 12 still inthe supercritical state, enters the refrigerant pipe 36, and passesthrough the internal heat exchanger 45.

The heat of the refrigerant is taken by the refrigerant which has flownout of the evaporator 17 on the low-pressure side, and the refrigerantis further cooled. By the presence of the internal heat exchanger 45,the heat of the refrigerant flowing out of the gas cooler 12 and passingthrough the internal heat exchanger 45 is taken by the refrigerant onthe low-pressure, and therefore supercooling degree of the refrigerantincreases the more. Therefore, the cooling capability in the evaporator17 is enhanced.

The refrigerant gas cooled by the internal heat exchanger 45 on thehigh-pressure side reaches the expansion valve 16. It is to be notedthat the refrigerant gas still has a supercritical state in the inlet ofthe expansion valve 16. The refrigerant is brought into a two-phasemixed state of a gas/liquid by pressure drop in the expansion valve 16.Moreover, the refrigerant brought into the two-phase mixed state flowsinto the evaporator 17 disposed in the bottom duct 219. There, therefrigerant evaporates, and absorbs the heat from ambient air to therebyexert a cooling function. It is to be noted that the air cooled by theevaporation of the refrigerant in the evaporator 17 enters the chamber273 via the holes 234, 234 by the operation of the fan 27 to therebycool the inside of the chamber 273. Furthermore, the air cooled by theevaporator 17 enters the duct 213 and the upper duct 220 by theoperation of the fan 27, and is sent to the storage chambers 270, 271,272 and the chamber 273 from the respective communication holes 237,238, 239, 240 and the holes 236, 236 to thereby cool the respectivestorage chambers 270, 271, 272 and chamber 273.

Moreover, by an effect to cool the refrigerant compressed by the firstcompression element by the heat exchanger 152 as described above, and aneffect to pass the refrigerant discharged from the gas cooler 12 on thehigh-pressure side through the internal heat exchanger 45 to cool therefrigerant, the refrigerant evaporates at lower temperature by theevaporator 17. Accordingly, the storage chambers 270, 271, 272 and thechamber 273 can be cooled at lower temperature, and the coolingcapability can be enhanced.

It is to be noted that the air (cold air) sent to the storage chambers270, 271, 272 and the chamber 273 repeats a cycle of cooling the storagechambers 270, 271, 272 and the chamber 273, thereafter being sucked intothe bottom duct 219 from the suction port 232, and cooled in theevaporator 17.

On the other hand, the refrigerant which has evaporated in theevaporator 17 flows out of the evaporator 17, flows in the refrigerantpipe 38, and passes through the internal heat exchanger 45. Then, therefrigerant repeats a cycle of taking the heat from the refrigerant onthe high-pressure side, and receiving the heating function to completelyturn to a gas state to be sucked into the first compression element ofthe compressor 11 from the refrigerant introducing tube 30.

(2) Mode to use Storage Chambers 270, 271 as Heating Chambers and useStorage Chamber 272 and Chamber 273 as Cooling Chambers

Next, an operation in a mode in which the storage chambers 270 and 271are used as the heating chambers for heating the articles, and thestorage chamber 272 and the chamber 273 are used as the cooling chambersfor cooling the articles will be described with reference to FIG. 14.

When the shelf 215 is inserted in the duct 213 by an operator (at thistime, the shelves 214, 216 are not inserted in the duct 213), the duct213 is vertically partitioned by the shelf 215. Accordingly, the storagechambers 270, 271 position on one side (upper side) of the shelf 215 areheated by the radiator 14, and the storage chamber 272 and the chamber273 positioned on the other side (lower side) can be cooled by theevaporator 17.

Moreover, the electromagnetic valve 70 is closed, and theelectromagnetic valve 72 is opened to thereby open the first bypasscircuit 40 by the control device (not shown). Accordingly, therefrigerant discharged from the compressor 11 does not flow in the gascooler 12, and all flows in the first bypass circuit 40 from therefrigerant discharge tube 34.

Furthermore, the control device starts operations of the electricheaters 80, 81 disposed on the shelves 214, 215 of the storage chambers270, 271. Accordingly, the storage chambers 270, 271 are heated. Thecontrol device starts the operations of the fans 27, 24. At this time,it is assumed that the fan 22 does not operate. Furthermore, the controldevice drives the driving element of the compressor 11. Accordingly, thelow-pressure refrigerant gas is sucked into the first rotary compressionelement (not shown) of the compressor 11 from the refrigerantintroducing tube 30, compressed to indicate an intermediate pressure,and once discharged to the outside of the sealed container from therefrigerant introducing tube 32. The refrigerant enters the intermediatecooling circuit 150. While passing through the heat exchanger 152 therefrigerant radiates the heat. However, since the fan 22 is not operatedin the present mode, the heat radiation of the refrigerant in the heatexchanger 152 slightly or hardly occurs. Thus, the refrigerant suckedinto the second rotary compression element can be held at hightemperature. Therefore, since the refrigerant discharged from thecompressor 11 is at high temperature, and the ambient air can be heatedat high temperature in the radiator 14, the heating capability in theradiator 14 can be secured.

Thereafter, the refrigerant is sucked into the second rotary compressionelement, compressed to form a high-temperature/pressure refrigerant gas,and discharged to the outside of the compressor 11 from the refrigerantdischarge tube 34. At this time, the refrigerant is compressed to anappropriate supercritical pressure.

Since the electromagnetic valve 70 is closed, and the electromagneticvalve 72 is opened as described above, the refrigerant gas dischargedthe compressor 11 flows in the radiator 14 disposed in the upper duct220 from the middle portion of the refrigerant discharge tube 34 via thefirst bypass circuit 40. Here, the high-temperature/pressure refrigerantcompressed by the compressor 11 does not condense, and is operated in asupercritical state. Moreover, the high-temperature/pressure refrigerantgas radiates the heat in the radiator 14. It is to be noted that theambient air heated by the heat radiation of the refrigerant in theradiator 14 enters the storage chamber 270 from the holes 236, 236 bythe operation of the fan 24 to thereby heat the heating chamber 270.Furthermore, the air heated by the radiator 14 enters the storagechambers 270, 271 from the communication holes 237, 238 via the duct 213by the fan 24 to heat the storage chambers 270, 271. In the presentinvention, since carbon dioxide is used as the refrigerant, therefrigerant does not condense in the radiator 14, therefore a heatexchange capability in the radiator 14 is remarkably high, and the airin the storage chambers 270, 271 can be set at the sufficiently hightemperature.

Moreover, the air (hot air) sent by the fan 24 is not sent below theshelf 215, because the duct 213 is partitioned by the shelf 215 asdescribed above. Accordingly, the storage chambers 270, 271 which arechambers above the shelf 215 can be heated.

On the other hand, the air (hot air) sent to the storage chambers 270,271 repeats a cycle of heating the storage chambers 270, 271, and beingthereafter sucked into the upper duct 220 from the suction port 230, andheated again in the radiator 14.

On the other hand, the refrigerant which has radiated the heat in theradiator 14 enters the refrigerant pipe 36 from the first bypass circuit40, and passes through the internal heat exchanger 45. There, the heatof the refrigerant is taken by the refrigerant which has flown out ofthe evaporator 17 on the low-pressure side, and the refrigerant isfurther cooled. By the presence of this internal heat exchanger 45, theheat of the refrigerant which has flown out of the radiator 14 andpasses through the internal heat exchanger 45 is taken by therefrigerant on the low-pressure side, and supercooling degree of therefrigerant increases the more. Therefore, the cooling capability in theevaporator 17 is enhanced.

The refrigerant gas cooled by the internal heat exchanger 45 on thehigh-pressure side reaches the expansion valve 16. It is to be notedthat the refrigerant gas still has a supercritical state in the inlet ofthe expansion valve 16. The refrigerant is brought into a two-phasemixed state of a gas/liquid by pressure drop in the expansion valve 16.Moreover, the refrigerant brought into the two-phase mixed state flowsinto the evaporator 17 disposed in the bottom duct 219. There, therefrigerant evaporates, and absorbs the heat from ambient air to therebyexert a cooling function. It is to be noted that the air cooled by theevaporation of the refrigerant in the evaporator 17 enters the chamber273 from the holes 234, 234 by the operation of the fan 27 to cool theinside of the chamber 273. Furthermore, the air cooled by the evaporator17 enters the duct 213, and is sent to the storage chamber 272 and thechamber 273 from the communication holes 239 and 240 by the operation ofthe fan 27 to thereby control the insides of the storage chamber 272 andchamber 273.

Here, the air (cold air) sent by the fan 27 is not sent above the shelf215, because the duct 213 is partitioned by the shelf 215 as describedabove. Accordingly, the storage chamber 272 and the chamber 273 whichare chambers below the shelf 215 can be cooled.

It is to be noted that a cycle in which the air (cold air) sent to thestorage chamber 272 and the chamber 273 cools the storage chamber 272and the chamber 273, and is thereafter sucked into the bottom duct 219from the suction port 232, and cooled again in the evaporator 17 isrepeated.

On the other hand, the refrigerant evaporated in the evaporator 17 flowsout of the evaporator 17, enters the refrigerant pipe 38, and passesthrough the internal heat exchanger 45. There, a cycle is repeated inwhich the refrigerant takes the heat from the refrigerant on thehigh-pressure side, receives the heating function to completely turninto a gas state, and is sucked into the first compression element ofthe compressor 11 from the refrigerant introducing tube 30.

(3) Mode to use Storage Chambers 270, 271, 272 as Heating Chambers anduse Chamber 273 as Cooling Chamber

Next, an operation in a mode in which the storage chambers 270, 271, 272are used as the heating chambers for heating the articles, and thechamber 273 is used as the cooling chamber for cooling the articles willbe described with reference to FIG. 15.

When the shelf 216 is inserted in the duct 213 by the operator (at thistime, the shelves 214, 215 are not inserted in the duct 213), the duct213 is vertically partitioned by the shelf 216. Accordingly, the storagechambers 270, 271, 272 position on one side (upper side) of the shelf216 are heated by the radiator 14, and the chamber 273 positioned on theother side (lower side) can be cooled by the evaporator 17.

Moreover, the electromagnetic valve 70 is closed, and theelectromagnetic valve 72 is opened to thereby open the first bypasscircuit 40 by the control device (not shown). Accordingly, therefrigerant discharged from the compressor 11 does not flow in the gascooler 12, and all flows in the first bypass circuit 40 from therefrigerant discharge tube 34.

Furthermore, the control device starts operations of the electricheaters 80, 81, 82 disposed on the shelves 214, 215, 216 of the storagechambers 270, 271, 272. Accordingly, the storage chambers 270, 271, 272are heated. The control device starts the operations of the fans 27, 24stored in the bottom duct 219 and upper duct 220. At this time, it isassumed that the fan 22 does not operate. Furthermore, the controldevice drives the driving element of the compressor 11. Accordingly, thelow-pressure refrigerant gas is sucked into the first compressionelement (not shown) of the compressor 11 from the refrigerantintroducing tube 30, compressed to indicate an intermediate pressure,and once discharged to the outside of the sealed container from therefrigerant introducing tube 32. The refrigerant enters the intermediatecooling circuit 150. While passing through the heat exchanger 152, therefrigerant radiates the heat. However, since the fan 22 is not operatedin the present mode in the same manner as in the above-described mode,the heat radiation of the refrigerant in the heat exchanger 152 slightlyor hardly occurs.

Accordingly, the refrigerant sucked into the second compression elementcan be held at high temperature. Therefore, since the refrigerantdischarged from the compressor 11 is at high temperature, and theambient air can be heated at high temperature in the radiator 14, theheating capability in the radiator 14 can be maintained.

Thereafter, the refrigerant is sucked into the second compressionelement, compressed to form a high-temperature/pressure refrigerant gas,and discharged to the outside of the compressor 11 from the refrigerantdischarge tube 34. At this time, the refrigerant is compressed to anappropriate supercritical pressure.

Since the electromagnetic valve 70 is closed, and the electromagneticvalve 72 is opened as described above, the refrigerant gas dischargedthe compressor 11 flows in the radiator 14 disposed in the upper duct220 from the middle portion of the refrigerant discharge tube 34 via thefirst bypass circuit 40. Here, the high-temperature/pressure refrigerantcompressed by the compressor 11 does not condense, and is operated in asupercritical state. Moreover, the high-temperature/pressure refrigerantgas radiates the heat in the radiator 14. It is to be noted that theambient air heated by the heat radiation of the refrigerant in theradiator 14 enters the storage chamber 270 from the holes 236, 236 bythe operation of the fan 24 to thereby heat the heating chamber 270.Furthermore, the air heated by the radiator 14 enters the storagechambers 270, 271, 272 from the communication holes 237, 238, 239 viathe duct 213 by the fan 24 to heat the storage chambers 270, 271, 272.In the present invention, since carbon dioxide is used as therefrigerant, the refrigerant does not condense in the radiator 14,therefore a heat exchange capability in the radiator 14 is remarkablyhigh, and the air in the storage chambers 270, 271, 272 can be set atthe sufficiently high temperature.

Moreover, the air (hot air) sent by the fan 24 is not sent below theshelf 216, because the duct 213 is partitioned by the shelf 216 asdescribed above. Accordingly, the storage chambers 270, 271, 272 whichare chambers above the shelf 216 can be heated.

On the other hand, the air (hot air) sent to the storage chambers 270,271, 272 repeats a cycle of heating the storage chambers 270, 271, 272,and being thereafter sucked into the upper duct 220 from the suctionport 230, and heated again in the radiator 14.

On the other hand, the refrigerant which has radiated the heat in theradiator 14 enters the refrigerant pipe 36 from the first bypass circuit40, and passes through the internal heat exchanger 45. There, the heatof the refrigerant is taken by the refrigerant which has flown out ofthe evaporator 17 on the low-pressure side, and the refrigerant isfurther cooled. By the presence of this internal heat exchanger 45, theheat of the refrigerant which has flown out of the radiator 14 andpasses through the internal heat exchanger 45 is taken by therefrigerant on the low-pressure side, and supercooling degree of therefrigerant increases the more. Therefore, the cooling capability in theevaporator 17 is enhanced.

The refrigerant gas cooled by the internal heat exchanger 45 on thehigh-pressure side reaches the expansion valve 16. It is to be notedthat the refrigerant gas still has a supercritical state in the inlet ofthe expansion valve 16. The refrigerant is brought into a two-phasemixed state of a gas/liquid by pressure drop in the expansion valve 16.Moreover, the refrigerant brought into the two-phase mixed state flowsinto the evaporator 17 disposed in the bottom duct 219. There, therefrigerant evaporates, and absorbs the heat from ambient air to therebyexert a cooling function. It is to be noted that the air cooled by theevaporation of the refrigerant in the evaporator 17 enters the chamber273 from the holes 240 via the holes 234, 234 or the duct 213 by theoperation of the fan 27 to cool the inside of the chamber 273.

Here, the air (cold air) sent by the fan 27 is not sent above the shelf216, because the duct 213 is partitioned by the shelf 216 as describedabove. Accordingly, the only chamber 273 which is the chamber below theshelf 216 can be cooled.

It is to be noted that a cycle in which the air (cold air) sent to thechamber 273 cools the chamber 273, and is thereafter sucked into thebottom duct 219 from the suction port 232, and cooled again in theevaporator 17 is repeated.

On the other hand, the refrigerant evaporated in the evaporator 17 flowsout of the evaporator 17, enters the refrigerant pipe 38, and passesthrough the internal heat exchanger 45. There, a cycle is repeated inwhich the refrigerant takes the heat from the refrigerant on thehigh-pressure side, receives the heating function to completely turninto a gas state, and is sucked into the first compression element ofthe compressor 11 from the refrigerant introducing tube 30.

(4) Mode to use Storage Chambers 270, 271, 272 and Chamber 273 asHeating Chambers

Finally, a mode to use the storage chambers 270, 271, 272 and thechamber 273 as heating chambers for heating articles will be described.In a state in which the operation of the compressor 11 is stopped, thecontrol device (not shown) starts the operations of the respectiveelectric heaters 80, 81, 82, 83 disposed on the respective shelves 214,215, 216, 217 to heat the respective storage chambers 270, 271, 272 andthe chamber 273. Accordingly, the storage chambers 270, 271, 272 and thechamber 273 can be heated.

As described above, also in the present embodiment, outside the storagechambers 270, 271, 272 and the chamber 273, the radiator 14, theevaporator 17, and the fans 24, 27 for sending the air which hasexchanged the heat with the radiator 14 and evaporator 17 are disposed,and the heating/cooling of each storage chamber can be switched.

Moreover, in addition to the heating by the radiator 14, when theelectric heater is used, the storage chambers 270, 271, 272 can besufficiently heated. Thus, when the electric heater is used in asupplementary manner in addition to the heating by the radiator 14,power consumption can be reduced.

Furthermore, in the present embodiment, in the mode to use all thechambers (storage chambers 270, 271, 272 and chamber 273) as the heatingchambers, the operation of the compressor 11 is stopped, and all thechambers 270, 271, 272, 273 are heated only by the respective electricheaters 80, 81, 82, 83. However, an evaporator for evaporating therefrigerant is disposed separately from the evaporator 17 in therefrigerant circuit 210. Furthermore, the channel control means forcontrolling the refrigerant circulation are disposed in the pipes on theinlet sides of both the evaporators. When the refrigerant is not passedthrough the evaporator 17, and is passed through the separately disposedevaporator to evaporate the refrigerant by the channel control means,all the chambers 270, 271, 272, 273 can be heated by the radiator 14.

1. A heating/cooling system having a storage chamber usable in such amanner as to be switched to be hot/cold, comprising: a refrigerantcircuit comprising a compressor, a gas cooler, a pressure reducingdevice, an evaporator and the like, containing carbon dioxide sealed asa refrigerant therein, and having a supercritical pressure on ahigh-pressure side; a radiator through which the refrigerant flowing outof the gas cooler flows before entering the pressure reducing device;and an air blower which sends air through the gas cooler, the inside ofthe storage chamber being heated by the radiator, the inside of thestorage chamber being cooled by the evaporator, and the air blower beingstopped in a case where the inside of the storage chamber is heated bythe radiator.
 2. The heating/cooling system according to claim 1,wherein the compressor comprises: first and second compression elements,the refrigerant compressed by the first compression element beingcompressed by the second compression element; and an intermediatecooling circuit comprising a heat exchanger for cooling the refrigerantcompressed by the first compression element, and allowing the secondcompression element to suck the refrigerant, and the heat exchanger isintegrally disposed in the gas cooler.
 3. The heating/cooling systemaccording to claim 1 or 2, further comprising: an internal heatexchanger for exchanging the heat between the refrigerant which hasflown out of the gas cooler and the refrigerant which has flown out ofthe evaporator, the refrigerant being passed through the radiator beforereaching the internal heat exchanger.
 4. The heating/cooling systemaccording to claim 1 or 2, further comprising: channel control means forcontrolling refrigerant circulation into the radiator and theevaporator; and an evaporator separately disposed for passing therefrigerant through the radiator, and evaporating the refrigerant in acase where the refrigerant circulation into the evaporator isinterrupted.
 5. A heating/cooling system having a storage chamber usablein such a manner as to be switched to be hot/cold, comprising: arefrigerant circuit comprising a compressor, a radiator, a pressurereducing device, an evaporator and the like, containing carbon dioxidesealed as a refrigerant therein, and having a supercritical pressure ona high-pressure side; and a partition member capable of dividing thestorage chamber in an insulated manner so that the inside of the storagechamber is heated by the radiator, and cooled by the evaporator, thepartition member dividing the storage chamber in such a manner that onechamber is heated by the radiator, and the other chamber is cooled bythe evaporator.
 6. The heating/cooling system according to claim 5, agas cooler for radiating heat from the refrigerant; a separateevaporator for evaporating the refrigerant; and channel control meansfor controlling refrigerant circulation with respect to the radiator,the gas cooler, and both the evaporators.
 7. The heating/cooling systemaccording to claim 5 or 6, wherein the compressor comprises: first andsecond compression elements; and an intermediate cooling circuit forcooling the refrigerant compressed by the first compression element ofthe compressor, and thereafter allowing the second compression elementto suck the refrigerant, and the cooling of the refrigerant in theintermediate cooling circuit is substantially invalidated in a casewhere the inside of the storage chamber is heated by the radiator.